Question

the parting fog made boats in the lake more visible.
infinitive
gerund
participle

Explanation:

To determine the correct term, we analyze "parting" in "parting fog". A participle (specifically a present participle) acts as an adjective, modifying "fog" here. An infinitive is "to + verb", and a gerund functions as a noun. "Parting" modifies a noun, so it's a participle.

Answer:

participle