On December 30, Burrows Inc. sold $12,000 of merchandise to Wall Company on account, with terms 2/10, n/30. The merchandise cost Burrows $8,000. On January 3, Wall determines that a portion of the merchandise received does not operate properly, and Burrows issues a credit memo for the returned items. The invoice amount of the returned merchandise is $3,000, which cost Burrows $2,000. Journalize the entries by Burrows to record 

(a) the December 30 sale,

(b) the January 3 return, and

(c) the receipt of the amount due from Wall on January 6.