Final answer:
In the Program Evaluation Review Technique (PERT), the amount of time needed to complete an activity is a mandatory element to be included. This method emphasizes on the scheduling aspects rather than costs or customer acceptance. It focuses on estimating and managing the time required for each activity in a project.
Step-by-step explanation:
The Program Evaluation Review Technique (PERT) is a tool used in project management that focuses primarily on the timing of tasks. It involves detailing all of the tasks necessary to finish a project, the order they must occur in, an estimate of how long each task will take, and the minimum amount of time needed to complete the whole project. When using PERT, one of the essential components to include is A. The amount of time needed to complete an activity. This involves estimating the shortest possible time, the most probable time, and the longest time that might be taken by an activity.
The question at hand does not refer to a requirement to include costs as in option B, the impact on labor costs as in option C, or the degree of acceptance by customers as in option D in a PERT analysis. While these factors might be important in other types of evaluations or for project management in a broader sense, they are not specific requirements for conducting a PERT analysis. The main focus of PERT is on the scheduling and timing aspects of project management.
It is important to maintain the evaluation of a project simple and executable, ensuring that it is understandable to program managers in terms of what is being done and why. Additionally, evaluating the cost/benefit using marginal cost and benefits helps in decision-making, but again, this isn't specifically required for PERT, which is more about time estimation and schedule management.