If a student rides her bicycle on a straight road and does not speed up or slow down, she is traveling with a a. constant acceleration. b. constant velocity. c. positive acceleration. d. negative acceleration.

The student would be travelling with a constant velocity.
Velocity is defined as the displacement divided by time where displacement is the difference between the final and initial positions. When a body or an objects travels the same distance every second, then the object is said to be moving with constant velocity.