Which sentence includes a gerund?

A. Swimming in the gulf is Finn’s favorite summer activity
B. While swimming at the beach Harper found a starfish.
C. Nash has been swimming since he was five years old.
D. Graham learn to dive at the community swimming pool.

A. Swimming in the gulf is Finn’s favorite summer activity

The sentence that includes a gerund is:

A. Swimming in the gulf is Finn's favorite summer activity.

To identify the sentence that includes a gerund, we need to first understand what a gerund is. A gerund is a verb form that ends in "-ing" and functions as a noun in a sentence.

Let's analyze each sentence to identify the one that includes a gerund:

A. "Swimming in the gulf is Finn's favorite summer activity." - In this sentence, "swimming" functions as the subject of the verb "is." It is a gerund because it ends in "-ing" and acts as a noun.

B. "While swimming at the beach, Harper found a starfish." - In this sentence, "swimming" is used as a present participle, which functions as part of a verb phrase. It does not act as a noun, so it is not a gerund.

C. "Nash has been swimming since he was five years old." - In this sentence, "swimming" is used as a present participle, acting as part of the verb phrase "has been swimming." It does not function as a noun, so it is not a gerund.

D. "Graham learned to dive at the community swimming pool." - In this sentence, there is no gerund.

Therefore, the sentence that includes a gerund is A. "Swimming in the gulf is Finn's favorite summer activity."