Which of the following sentences contains a dangling modifier?
a. playing with the children, it was obvious they had a good time.
b. the nurse arranged the medication on the try while talking to the doctor.
c. in order to get good grades, you need to apply yourself more in class.

A dangling modifier is a type of a modifier which is placed incorrectly or the noun it is supposed to modify isn't clearly stated in the sentence.
Having this in mind, the sentence which contains a dangling modifier is A. Playing with the children, it was obvious they had a good time.

It should be rewritten somehow to say: It was obvious they had a good time playing with the children. 

Yes, but depends on the type of song the singer classifies it to be!

Explanation: