Initially, I chose B, but on BR I chose C.

And this was my reasoning: the fact that "the standard keyboard allows skilled operators to achieve considerable typing speed" answered why people do not have to switch to a different keyboard layout. It is necessary, since considerable typing speed is achievable. And the second part, "though it makes acquiring such skills relatively difficult," shows that it is actually true that they intended the layout to slow down the speed.

oh well..

These are kinda fun!

4/5

2/5

Taking in august. Would love to join!!

Same here. I just skimmed this lesson. I can come back to it later, once I've encountered a question that requires this rule application.