The principle that managers follow when they only investigate departures from the plan that appears to be significant is commonly known as:

a. small amounts don’t matter.
b. management by exception.
c. only labor and materials deserve attention.
d. exceptional costs yield exceptional results.

B. management by exception.

Explanation:

Management by exception, as the title suggest is the management of the activities which have a highlighting impact on the performance of activities accepted.

Basically when there is a difference in the activity level, which causes a major deviation from the acceptance level, then the management in priority investigates such transactions and then accordingly tries to find the loop holes in the planning and execution of tasks.

In this manner, the management chooses to investigate the activities which are significantly different from the ones that are planned.

answer; schedule c;