Recievable control account reconcilation

Good day to you I came across a question that was in regard with reconcilations of the control account Which of the following errors should be identified by performing a recievables control account reconcilation? A A sales invoice of $500 has been omitted from the sales daybook B A sales return of $45 entered as $54 in the sales return daybook C Purchases of $72 were entered as sales returns in the sales returns daybook and the indivual account D The total of the sales daybook was miscast by $200 The correct answer was D but my answer was A First of all I eliminated the options B and C because....B was referring to a sales return book..(So far I son't think thats relevant to a sales control account or the indivual balances) I eliminated C because it was talking about entering wrong figures in the sales return daybook and not the control account Then for me choosing the wrong answer..this was the approach I took as follows below It said that the the sales invoice was omitted from the daybook so I assumed that the figure was entered in the ledger balances(the indivual balances) but not in the control account. Hence there would be a difference obviously in both the control and ledger balances Please let me know whether the way I eliminated option B and C is correct I wanted to know why this A answer wasn't correct either and D was the answer instead