Motorcyclists face distinct dangers because they a. are hard to see b. are not entitled to use a full lane c. do not have the same legal protections as cars and trucks d. all of the above

A. Are hard to see

Explanation:

Motorcyclists have the same responsibilities and rights as car and truck drivers. The same rules apply to all of them (the motorcyclists are also entitled to a full lane), but an important difference is the lack of visibility in the motorcyclists' case. To decrease the issue, many motorcycles have headlights that automatically turn on when the vehicle starts moving.

Measures of precaution are expected from the car and truck drivers, too. For example, they shouldn't only check their mirrors, but do a visual check as well, as motorcycles can easily end up in the blind spot of the vehicle. The drivers should dim their headlights while approaching a motorcycle as, for them, the blinding effect is greater.