Credit terms of $\frac{1}{10},\frac{n}{30}$ mean that $*$

A$)$ a discount is allowed if the bill is paid within $30$ days.

B$)$ a discount is allowed if the bill is paid after $10$ days.

C$)$ a $1\%$ discount is allowed if the customer pays the bill within $30$ days.

D$)1\%$ discount is allowed if the bill is paid within $10$ days, or the entire amoun

within $30$ days.