The correct answer is the role of adjective. Both non-finite verbs can perform the role of adjective in a sentence. The following examples show this role:
Present participle as adjective, which can be recognized from its "-ing" ending:
Look at the reading boy.
Past participle as adjective, which are formed by adding "-ed" to the verb:
Participles can function as adjectives when they end in -ing or -ed.
A participle that is ending in "ing" (present participle) is used for describing an object. Example: an interesting book. (Present participle: interesting).
When the participle functions as an adjectibe and ends in "ed" (past participle), it is used for talking about people. Example: The kid is bored. He is interested in video games. (Past participles: bored - interested).
