2016 Pascal Problem 1

The result of the addition shown is

\begin{array}{r} 300 \\ 2020 \\ +\ 10001 \\ \hline \end{array}

\textbf{(A)}\ 15021\quad \textbf{(B)}\ 12231\quad \textbf{(C)}\ 12051\quad \textbf{(D)}\ 13231\quad \textbf{(E)}\ 12321

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Pascal contests here.