I would hope that clear and concise writing takes precedence over flexing a large vocabulary

After a few months of studying this is the first time I have a serious bone to pick with a question.

I saw the issue with E but thought D had to be wrong. Best-selling doesn't mean large readership. What if everyone buys a pretentious book to look smart and nobody actually reads it? That seems like exactly the kind of assumption other questions punish us for making...

I see why A is a great answer, but for B, what makes the first sentence not a principle? "Scientists...need to ask themselves if their investigation is motivated by...mere curiosity."

That seems like a principle that Varila disputes the validity of. "Scientists don't need to ask themselves if their investigation is motivated by mere curiosity because mere curiosity can lead to scientific discoveries."

Ultimately, I see that A is even better, but I want to understand why B is definitely wrong...

I'm seriously so impressed with anyone doing this test with a different first language!!