Final answer:
Option (A), In network diagrams such as PERT or CPM, the connections between project activities indicating the flow direction are called arcs.
Step-by-step explanation:
The connections between project activities that indicate the flow direction are technically referred to as arcs. These are graphical representations of the relationships between tasks in network diagrams like a Program Evaluation Review Technique (PERT) or a Critical Path Method (CPM) chart. In such diagrams, tasks or activities are depicted as nodes or vertices, and the connections or arcs show the sequence or dependency between them, indicating which tasks must be completed before others can start.