Which schedule compression technique involves performing activities in parallel for a portion of their duration?

The correct answer is C, Fast Tracking. This technique involves re-scheduling activities so that certain tasks, which would normally be performed sequentially, are instead carried out concurrently for part of their duration. By overlapping tasks, the project timeline can be shortened without changing the scope of the project. This approach is particularly useful when the schedule is tight or when leveraging available resources effectively to meet deadlines.

Fast tracking does, however, carry some risks, such as increased complexity and potential for rework, as the tasks being performed in parallel may influence each other.

In comparison, resource leveling focuses on balancing resource allocation and may delay some activities to avoid overallocation, while crash time refers to adding resources to reduce the time required for specific tasks without overlapping them. The Critical Path Method is a project management technique used to identify the longest stretch of dependent activities and measure project duration, but does not inherently involve altering the sequence or overlap of tasks. Hence, these choices do not align with the definition of performing activities in parallel for a portion of their duration.