What adjective describes coming to work on the bus compared to using an old bicycle?

The adjective "easier" is the correct choice because it serves as the comparative form of "easy." When comparing two modes of transportation—coming to work on the bus versus using an old bicycle—it is appropriate to express that one option has a greater degree of ease than the other. In this context, saying that taking the bus is "easier" than riding a bicycle implies that it requires less effort or is more convenient.

Choosing this comparative form effectively communicates that you are comparing the two alternatives directly, making it clear which option is more favorable in terms of ease. The other options either do not fit the comparative context or do not maintain the same level of specificity about the comparison being made.