AMC 10 2021-fall-b Problem 3

The expression $\frac{2021}{2020} - \frac{2020}{2021}$ is equal to the fraction $\frac{p}{q}$ in which $p$ and $q$ are positive integers whose greatest common divisor is ${ }1$. What is $p?$ $(\textbf{A})\: 1 (\textbf{B}) \: 9 (\textbf{C}) \: 2020 (\textbf{D}) \: 2021 (\textbf{E}) \: 4041$