For the year just ended, XYZ Inc. had average accounts receivable of $925,000 and total credit sales of $4,200,000. Throughout the year, a factor purchased accounts receivable from the firm at a 3.5% discount. What was the firm's effective interest rate paid on its receivables financing?

A) 11.6%

B) 13.4%

C) 15.7%

D) 16.3%

E) 17.6%