Construction of the Cattery Could Be Distilled to Eight Distinct

Multiple Choice

Construction of the cattery could be distilled to eight distinct steps, from the official groundbreaking ceremony to the cutting of the litterbox ribbon. The activities, their durations and predecessors are shown in the table below. Use this scenario to answer the following question. $$\begin{array} { | c | c | c | } \hline \text { Activity } & \text { Predecessors } & \text { Time (weeks) } \\\hline \text { A } & \cdots & 10 \\\hline \text { B } & \text { A } & 8 \\\hline \text { C } & \text { A } & 7 \\\hline \text { D } & \text { C } & 11 \\\hline \text { E } & \text { D } & 12 \\\hline \text { F } & \text { B } & 11 \\\hline \text { G } & \text { E, F } & 6 \\\hline \text { H } & \text { E, F } & 9 \\\hline\end{array}$$ Refer to the scenario above. One activity has identical earliest finish and latest start times. What is the common number for this unusual activity?

A) 17
B) 18
C) 21
D) 29