Mercutio has ill-will towards both of them
The answer to your question would be that, to ensure the sentence has a parallel structure, the third phrase should begin with a noun.
Parallel structure, also known as parallelism, is the repetition of a given grammatical structure within a sentence or passage in order to show that two or more ideas have the same level of importance.
Answer:
B) The author is informed and concerned about heatstroke.
