You are working on your network diagram. Activity $A$ is a predecessor to Activity $B.$ Activity $B$ cannot begin until Activity $A$ is completed. What is this telling you?

A $$ Activity A and Activity $B$ are both on the critical path.

B $$ Activity $B$ is a successor to multiple tasks.

C There is a mandatory dependency between Activity A and Activity B$.$

D $$ There is a finish$-$to$-$start dependency relationship between Activity A and Activity $B.$