Question

In which sentence is the word singing a gerund? A. The hikers enjoyed the singing birds. B. The birds are singing a cheerful song. C. The birds’ singing filled the park. D. The birds kept singing.

Answer 1

Correct Answer : " The Birds' Singing Filled The Park. " 

Answer 2

The sentence in which the word "singing" is a gerund is C, "the birds' singing filled the park".  Gerunds are words that are formed with verbs but act like nouns.  This means that they can be the subject, the direct or indirect object of a sentence, subject complements and the complements of a preposition in a prepositional phrase. In this case, the gerund "singing" together with "the birds" function as the subject of the sentence. You can tell this by asking the following the question: Who did fill the park ? --> The birds' singing.