Which of the following statements is true?

a. you must always stop if you are moving in the same direction as a school bus and you must remain stopped until the bus stop signal is withdrawn.

b. if the highway is divided by a raised barrier or an unpaved median at least five feet wide, you do not have to stop for a school bus traveling in the opposite direction.

c. on a two way street or highway, all drivers moving in either direction must stop for a stopped school bus which is picking up or dropping off children and remain stopped until all children are clear of the roadway and the bus signal is withdrawn.

d. all of the above