AMC 10 2021-fall-a Problem 2

Menkara has a $4 \times 6$ index card. If she shortens the length of one side of this card by $1$ inch, the card would have area $18$ square inches. What would the area of the card be in square inches if instead she shortens the length of the other side by $1$ inch? $\textbf{(A) } 16 \textbf{(B) } 17 \textbf{(C) } 18 \textbf{(D) } 19 \textbf{(E) } 20$