Merchandise Was Sold on Credit for $30,000,terms 3/15,n/30

Merchandise was sold on credit for $30,000,terms 3/15,n/30.Which of the following journal entry descriptions correctly describes the cash collection?

A) Cash is debited for $29,100 and accounts receivable is credited for $29,100 if the collection is within the discount period.
B) Cash is debited for $29,100, sales discounts is debited for $900, and accounts receivable is credited for $30,000 if the collection is within the discount period.
C) Cash is debited for $30,000, accounts receivable is credited for $29,100, and sales discounts is credited for $900 if the collection is within the discount period.
D) Cash is debited for $29,100 and accounts receivable is credited for $29,100 if the collection is after the discount period.