Use the above network diagram and activity lengths in the nodes to determine the early start time for activity D $(1$mark$)$

A$)8$

B$)13$

C$)14$

D$)21$

Use the above network diagram and activity lengths in the nodes to determine the late start time for activity F$.(1$ mark$)$

A$)21$

B$)24$

C$)26$

D$)23$