2. in which one of the following sentences is but used as a preposition? a. i would like to return to italy, but i have no money. b. i wanted to leave, but i was embarrassed to do so. c. the lake is pretty, but it's too cold for swimming. d. we discovered that candy will do anything but work.

The correct answer is D. We discovered that Candy will do anything but work.
In sentences A, B, and C, the word but is used as a conjunction - it connects two independent clauses within one large sentence. However, in example D, the word but is used with the meaning of apart from which is a preposition, so but also functions as a preposition here.

This is literary work