Critical Reasoning

Conclusion: Commuting plan saved money

Evidence: Volunteers who commuted had higher sales

Assumption: This high sales isn't temporary

Question: What would HURT this plan?

Prediction: If the assumption was false. That is: high sales = a fluke.

A - shows it's a fluke b/c it's all the employees who work hard anyway

Because of the word "these", it's clear 1) is implied. The sales of THESE bankers were higher than their sales previously.

For CR, it always comes down to the crux of the argument. Even though the workers are naturally hard-working, the fact that they are "most loyal" also proves the assumption false, since if they were "loyal" they would likely want to help the company save $$.