With which of the following costs should a foreman be most concerned?

A foreman should be most concerned with labor costs because labor typically represents one of the largest expenses in any construction project. Managing labor effectively is crucial to ensure that a project stays within budget and on schedule. This involves monitoring wage rates, overtime, productivity levels, and ensuring that the labor force is properly utilized for the tasks at hand.

By focusing on labor costs, a foreman can directly influence project efficiency and profit margins. While materials, overhead, and equipment rental are also important, the management of labor has a more immediate and significant impact on productivity and project completion. Effective labor management can lead to better project outcomes, including timely completion and lower overall costs, which is why it is a primary concern for those in a foreman's position.