AMC 10 2020b Problem 4

The acute angles of a right triangle are $a^{\circ}$ and $b^{\circ}$, where $a>b$ and both $a$ and $b$ are prime numbers. What is the least possible value of $b$? $\textbf{(A)}\ 2 \textbf{(B)}\ 3 \textbf{(C)}\ 5 \textbf{(D)}\ 7 \textbf{(E)}\ 11$