SC

This question is not the greatest, and none of the versions of the sentence strike me as being particularly effective.

Having said that, I agree with you.

For one thing, choice A has two clear issues.

One is that the pronoun it does not clearly refer to anything. Possibly it refers to a song, but if it does, then the meaning conveyed is that if a song is played often, the song itself, rather than playing the song, increases the chance (likelihood would be a better word), that the singer will become famous, which meaning does not make sense.

The second is that "If a song is played on the radio often", is not a noun. So it cannot be a practice.

So A is not correct.

B has the same issue.

C is a little funny too though. Is a practice a song?

D has pretty much the same issue that C has.

E has even more issues.

Maybe C is the best, but it's not really correct.

To make C, or D, really correct you would need to make clear that the practice is not the song but rather playing the song. So you need the gerund form of play, playing. Here's how a correct from would look.

Playing a song on the radio often, a practice favored by popular radio stations, increases the likelihood that the singer of the song will become famous.