Task A has the following details：Optimisti

问题：

Task A has the following details：Optimistic estimate=30, pessimistic estimate=40, most likely estimate=35. Task B has the following details：Optimistic estimate=32, pessimistic estimate=37, most likely estimate=34. Task C has the following details：Optimistic estimate=25, most likely estimate=35, pessimistic estimate=45. Which task has the highest standard deviation （）

A. Task A. 

B. Task B. 

C. Task C. 

D. Task A & Task C.