AMC 8 1993 Problem 10

This line graph represents the price of a trading card during the first $6$ months of $1993$.

The greatest monthly drop in price occurred during $\text{(A)}\ \text{January} \text{(B)}\ \text{March} \text{(C)}\ \text{April} \text{(D)}\ \text{May} \text{(E)}\ \text{June}$