Respuesta :
The correct answer is option three.
The -ing gerund works as a noun and is commonly used as the subject of the sentence. In this example, the gerund is the verb "volunteering," which takes a complement, "at the animal shelter." Therefore, the entire clause "Volunteering at the animal shelter," is considered a noun, which serves as the subject of the whole sentence.
Option 3: The phrase acts as a noun that is the subject of the sentence.
"Volunteering at the animal shelter in my neighborhood" is a gerund phrase (It begins with a gerund, the "ing" word, and includes others modifiers and objects), and gerund phrases always function as nouns. Therefore, the phrase in the passage acts as a noun, which at the same time is the subject of the sentence since it's what's being discussed.