Answer:
A). The gerund is "painting."
C). The gerund is acting as a noun.
E). The gerund could be replaced with an infinitive.
Step-by-step explanation:
Gerund are elucidated as the words that are formed out of verbs but function as nouns in the sentence. It is formed by putting '-ing' as suffix to main verb which seems quite identical to present participle but gerunds are distinguished as they function as nouns.
In the given question, options A, C, and E assert true claims concerning gerund and its use in the sentence. 'Painting is gerund in the sentence as it functions as a noun in it. It can replaced with an infinitive 'to paint' as it can replace the noun 'painting.' Thus, options A, C, and E are the correct answers.