Do you always go to school . . . . . foot? A. on B. by C. with D. walking

The correct answer is D. walking.

The other options are incorrect because:

• A. on is used to indicate a means of transportation, such as “on foot” or “on a bike.”
• B. by is used to indicate a mode of transportation, such as “by car” or “by train.”
• C. with is used to indicate that someone or something is accompanying you, such as “I went to school with my friends.”

The question is asking how the person goes to school, and the only option that indicates a means of transportation is D. walking.