Question

which word best completes the sentence? sahil plunged ____ into marine biology fieldwork this summer, quickly volunteering to survey oysters along the reefs at point pinole regional shoreline. hither foremost headlong consequently

Explanation:

"Headlong" means in a rushed or impetuous manner. It fits the context as Sahil quickly and eagerly got into marine - biology fieldwork. "Hither" means to this place, which is not appropriate. "Foremost" means most important or leading, not relevant here. "Consequently" means as a result, which also doesn't fit the action of plunging into the work.

Answer:

C. headlong