From the Following Data Calculate the Estimated Cash Received from Total

From the following data calculate the estimated cash received from total sales for December.
Total sales for October,$10 000;
November,$15 000;
December,$14 000
Credit sales are normally settled in the pattern,30% for cash,40% in the month of sale,30% in the month following the sale,and the balance in the second month following the sale.

A) $14 000
B) $11 400
C) $13 800
D) $10 500