Jonny is solving this equation for n: 8+3n= 20. His first step is to subtract 8 from both sides of the equation. Why?

A. He needs to reserve the order of operations
B. He needs to follow the order of operations
C. 8 is attached to 3n by subtraction
D. 8 is the first term in the equation

D. 8 is the first term in the equation