One of the Processes Within Requirements Analysis Is to Prioritize

One of the processes within requirements analysis is to prioritize requirements. As a business analyst why would you ever want to prioritize requirements?

A) You may need to determine the cost of each requirement.
B) You may need to determine the schedule for each requirement.
C) You may need to determine which requirements are most critical so the analysis and implementation efforts focus on the most critical requirements.
D) You may need to determine which requirements are most critical so additional risk analysis can be completed on those requirements.