Answer is C - Gap Analysis:
BABOK V-3 6.4.2 GAP Analysis pg.127 Gap analysis can help identify the gaps that prevent the enterprise from meeting needs and achieving goals. It can be used to determine if the enterprise can meet its needs using its existing structure, resources, capabilities, and technology. If the
enterprise can meet the need with the current state capabilities, then the change will likely be relatively small, or there may be no change at all. In any other case, a change strategy is needed to create the missing capabilities or improve the existing ones.
BABOK V-3 6.4.4 Change Strategy pg.128 - A change strategy is a high-level plan of key activities and events that will be used to transform the enterprise from the current state to the future state. Change strategies may be a singular initiative composed of smaller changes which might be structured as a set or sequence of projects, or as various continuous improvement efforts. Each element of change might not completely address the need, so multiple changes might be necessary.