The correct answer is B. Incidentally.
Explanation
Linking Words are words that are used to relate ideas within a paragraph. To select the appropriate linking word it is necessary to know the context of the sentence to give cohesion and coherence to the text. In the sentence presented, the appropriate linking word is "incidentally" because the idea "wearing certain colors may also attract mosquitoes" acts as a complementary information and the linking word "incidentally" can be used to add ideas. So, the correct answer is B.
