You're driving on the highway an hour before sunset, but you can barely make out the vehicle 500 feet in front of you. what should you do?

Turn on your headlights if you couldn't see the vehicle 500 feet in front of you.

Explanation:

Headlights of the vehicle should be turned ON; when the driver couldn’t see the vehicle at a distance of 500 feet even it is an hour before sunset. The headlight can be turned ON at any time when the driver feels difficulty in seeing other vehicles.

In general the headlights are turned on 30 minutes before sunrise and 30 minutes after sunset. But nothing is wrong if the headlight runs throughout the driving time. Many countries follow a law that the headlights should be turned on at all times.

rain should be the answer.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."