Respuesta :
the second one, sailing can be used as a verb but in this cause it is an activity which is a noun
Answer:
Sailing is my aunt and uncle’s favorite activity.
Explanation:
In the English language when a verb serves the same function as a noun in the sentence, it is called a gerund. For this, the verb has to have the -ing ending.
In the correct answer, Sailing is a noun functioning as the subject of this sentence.