A misplaced modifier changes the meaning of a sentence by being in the wrong place: "Sally found her doll playing under the swing set."
The writer means to say Sally was playing under the swing set. Instead we get this creepy image of a doll playing under the swing set. It's easy to fix because we know Sally found the doll.
A dangling modifier leaves the intended subject out. "While playing under the swing set, Sally's lost doll was found by her."
A dangling modifier is unclear and hard to fix. Who found the lost doll? The reader has to guess.
In this case, the meaning is changed: the soccer ball is running on the track.
Also, it's hard to fix because it's unclear: who got hit with the soccer ball?
So the answer is that it's both a misplaced modifier and a dangling modifier, C.
