In the sentence “The accountant desires to be honest rather than rich”, the type of verbal is “infinitive”. The infinitive form of a verb is preceded by the preposition “to” which in this case is “to be”.
A gerund is a verbal acting as a noun and it is form by “verb+ing”. A participle is a verbal acting as an adjective and it is formed by past form of verb. So in this case the only answer that applies is “infinitive”