What does this sign mean?

a. the hov lane may be used only by vehicles with two or more occupants at the indicated time.
b. drivers may enter the hov lane only during the indicated hours.
c. during the posted hours, drivers should use the hov lane to get to downtown.
d. the hov lane is reserved for drivers with disabled plates or placards.

The answer is A, because an HOV lane is used for people with 2 or more persons in the vehicle. There is usually a set time that people can use the HOV lane. It was made like that because people thought that when somebody would carpool or drive a coworker to their job, it would be a much faster and convinent way because the speed limit is higher in the HOV lane.