Answer:
B. VACATIONING is an important thing to do with your family
Step-by-step explanation:
A gerund is a type of verbal that does not act as a verb in a sentence but as a noun. This verbal is formed with the root of a verb + the ending -ing. The word “Vacationing” in option B is an example of a gerund because it is acting as a noun in the sentence, that is, as a word that names the activity or practice of taking vacations. Besides, this gerund is also the subject of the sentence because it is what's being talked about.