What Is the Expected Value for the Upper Left-Hand Cell $\begin{array}{ll}15 & 21 \\25 & 20\end{array}$

What is the expected value for the upper left-hand cell of the following 2x2 table? $\begin{array}{ll}15 & 21 \\25 & 20\end{array}$

A) 18.0
B) 17.8
C) 15.0
D) 8.3