AMC 8 2009 Problem 15

A recipe that makes $5$ servings of hot chocolate requires $2$ squares of chocolate, $\frac{1}{4}$ cup sugar, $1$ cup water and $4$ cups milk. Jordan has $5$ squares of chocolate, $2$ cups of sugar, lots of water, and $7$ cups of milk. If he maintains the same ratio of ingredients, what is the greatest number of servings of hot chocolate he can make?

$\textbf{(A)}\ 5 \frac18 \textbf{(B)}\ 6\frac14 \textbf{(C)}\ 7\frac12 \textbf{(D)}\ 8 \frac34 \textbf{(E)}\ 9\frac78$