What is the main reason to prioritise the test cases?

It is possible that the test execution phase will be shortened and that test cases will need to be prioritised.

What is the main reason to prioritise the test cases?
A . Get the areas the programmer is most worried about finished first
B . Get finished within the time and budget available
C . Ensure that when you stop you have done the best tests in the time available
D . To ensure as many tests as possible are run

Answer: C