I believe it's C. Taking public transportation can benefit a person financially, create new social connections, and reduce stress. If you're taking the writing an informative essay about making sacrifices.
The strongest thesis for such an essay would be to promote green transportation especially if transit is electric and doesn't involve the burning of hydrocarbons as most cars still do. When many people say take a bus or a subway or skytrain they are preventing that much gas fumes from being put in the atmosphere and so they are opposing global warming by their actions.
