Self-study
Braille is a method of producing text by means of raised dots that can be read by touch. █ ██████ ███████████ ██ ██████████ ████ █████ ████ ████████ ███████ ██ ██ ████ ██ █ ████████ ████ ███ ██ ██████ ██ ████████ ████ █████████ ███ ████████ ████ ██ ████████ █████ ███ ███████ ██████ ████ ███████ ███ ████ ██████ ██████ ██ ████████ ██ ███████ ████ ██████ ███ ██ ██████████ ██ ███████ ███████ ███ ██████ █████ ██ ███ ███ ██ ████ ██████████ ███████
Objective: Find a Necessary Assumption
The author concludes that a new electronic braille system, which works by heating a device's screen in specific patterns, will be accessible to anyone who can read traditional braille. In support, the author explains that the new electronic braille system uses the same symbols as traditional braille.
The author's argument is based on an analogy between traditional and electronic braille: their similar features are used to support the claim that readers will be similarly able to use them. But the author only addresses one point of comparison between the systems, that they use the same symbols. The author doesn't address any other potential barriers to reading electronic braille. For instance, we don't know if people's fingers can actually sense a pattern of heat the way they can distinguish raised dots on a surface. For electronic braille to be usable for traditional braille readers, the author has to assume that there won't be other significant barriers to its use.
As with many Necessary Assumption questions, though, we should keep an open mind when reading the answer choices. Necessary assumptions can come in many forms, so we shouldn't make the (unwarranted) assumption that we've predicted the only possible answer!
1.
Which one of the following ██ ██ ██████████ ██ █████ ███ ██████████ ████████
a
Braille is the ████ ██████ ██████ ████ ███ ██ ███████ ███████ ███ ███ ████ ███ ███ ███████ ███████
The author only claims that braille readers will be able to use this new electronic braille system, so whether any other systems can be adapted or not is beyond the scope of the argument. Whether (A) is true or not doesn't affect the strength of the author's reasoning, meaning (A) isn't necessary.
b
Only people who █████████ ███ ███████ ██ █████ ████ ██████ ███ ███████ ████ ████ ████ ███ ████████ ██ █████ ██ ███ ███ ██ ███ ███████ ███████
When the author talks about people who have the ability to read in braille, that includes people who read both with braille and with other systems. The author doesn't distinguish people who read with other systems, as long as they can still read in braille, so it's not necessary to assume such a distinction.
c
People with the ███████ ███████ ██ ████████████ ███████ ██ ███████ ████ ██ ███████ ██ ████████████ ███████ ████████ ██ █ ████ ██████ ████████
This must be true in order for the conclusion to follow. If braille readers didn’t have the ability to distinguish symbols using heat, then they wouldn’t easily adapt to the new system despite the symbols being the same. So negating (C) would break apart the argument, meaning it's necessary to assume (C).
d
Some symbol systems ██████ █ █████ ██ ████ ██ █████ ████ ████ █████████ ███ █████ ██ ███████ ██ ███ █████████
The argument is only about braille; even with the new electronic braille system, we know that the symbols used will match those of traditional braille. The exact symbols used in braille or any other system, alphabet-shaped or otherwise, don't make a difference to the argument.
e
Eventually it will ██ ████████ ██ █████ ██████ ██ ████ ███████ ██ █████ ████████ ████ ██ ███ ███ ██ ███ ███████ ███████
The conclusion is just about people who already know traditional braille being able to read electronic braille. Whether the learning process will be able to go the other way in the future doesn't affect the argument, so it can't be necessary to assume.