Diagram shows the sequence of activities for project xyz and its duration, The project manager is asked to reduce the project duration by two weeks, None of the activities can be fast tracked. Activities A and F cannot be crashed; activity G can be crashed by two weeks; and all other activities can be crashed by one week.To meet the new project duration requirement, which of the following will the project manager decide to do?

A、Crash activity G

B、Crash activities C and D

C、Crash activities G and C and D

D、Crash activities G and F and C