Answer: The gerund in the sentence provided is "wearing".
Explanation: A gerund is a non-finite verb form that ends in -ing and acts as a noun. Moreover, a gerund can act as the subject, the direct object, the subject complement or the object of a preposition in a sentence. In the sentence provided, "wearing" is the only gerund as "wearing" is acting as a noun and functioning as the object of the preposition "for". In contrast, "waiting", "chattering" and "complaining" are present participles.
