A construction project manager is overseeing the development of a new residential building. During the inspection of the concrete structure, the team notices the presence of honeycombing. Honeycombing refers to the formation of voids or gaps in the concrete, typically caused by inadequate vibration during the pouring and setting process.

Question:

What is the primary cause of honeycombing in concrete structures?

A) Excessive use of admixtures B) Insufficient curing time C) Overuse of formwork D) Inadequate vibration during concrete placement