How do the media affect which issues the public thinks are important? A.
by the number of stories they report on an issue or the amount of time they spend covering an issue
B.
by telling people what opinion they should have on an issue
C.
by including multiple sides of an issue during a news report
D.
by the number of advertisements or commercials they sell in support of an issue

If there is this choice then it is all of them.

Explanation:

Media itself is basically something where politics can use to manipulate the viewers, however the means on how they are doing it gives a certain vibe which you'll probably learn later. But if it is only one answer would be C or B from an unbiased or moderate point of view.

A.

by the number of stories they report on an issue or the amount of time they spend covering an issue

Explanation:

answer; cultural trait;