What does a non-flashing yellow light at a traffic light indicate?

A)Pass with caution.
B)Stop as if it were a steady red light.Correct
A non-flashing yellow light means that vehicles must stop under the same conditions as if it were a steady red light, unless when it lights up the vehicle is so close to the stopping point that it cannot stop before it under sufficient safety conditions.
If the light is flashing yellow or two yellow lights flashing alternately, drivers are obliged to use extreme caution and, where appropriate, give way. In addition, they do not exempt from compliance with other signs that require stopping.