单选题：The following figure shows the AOE network of a project with 8 a

The following figure shows the AOE network of a project with 8 activities. The earliest and the latest completion times of the vertex `4` are __, respectively.



@[C](2)

A. 12 and 12
B. 12 and 14
C. 19 and 19
D. 19 and 23



A.12 and 12
B.12 and 14
C.19 and 19
D.19 and 23


答案：C