Simple versus Add$-$On Interest. Why are loan payments under the simple interest method usually lower than loan payments under the add$-$on interest method?

Loan payments under the simple interest method are usually lower than loan payments under the add$-$on interest method because the: $($Select the best answer below.$)$

A$.$ interest remains the same throughout the loan period.

B$.$ interest is calculated on the remaining balance.

C$.$ principal decreases over time.

D$.$ principal is paid off first.