10. The prime factor decomposition of 2021 is $43 \times 47$. What is the value of $53 \times 57$ ?
A 2221
B 2521
C 2921
D 3021
E 3031
10. D Note that $53 \times 57=(43+10)(47+10)=43 \times 47+43 \times 10+10 \times 47+10 \times 10$ $=2021+(43+47+10) \times 10=2021+100 \times 10=2021+1000=3021$.