How do you calculate net sales?

Question $54$ options:

Net Sales $=($promotional allowances $$ gross profits$)$

Net Sales $=($customer returns $+$ customer sales $+$ customer allowances$)$

Net Sales $=($operating expense $+$ interest expense$)($gross sales$)$

Net Sales $=($gross sales $$ cogs$)$

Net Sales $=($gross sales$)($customer returns $+$ promotional allowances from vendors$)$