3. Kanye West
No one gets more impact out of everything he does than Kanye. One interview from the man is talked about more than most artist's songs; one song can change music's landscape in a way most artists can't with entire albums.
Time flies, so while it may feel like "All Day" dropped ages ago, it was absolutely a March release, and it was absolutely one of the best songs of the month. Pair the audio release with the more-than-memorable live performance at the Brit Awards and once again his royal Yeezyness finds himself near the top of the rankings, although like Drake he's going to have to do more work in April or he'll really start falling.
On the other hand, if April brings the surprise album 'Ye's hinted at releasing, Kendrick's going to find himself fighting for the top spot.