Hardcastle Furniture Is a Retailer of Fine Leather Sofas,chairs,and Ottomans

Hardcastle Furniture is a retailer of fine leather sofas,chairs,and ottomans.It bought advertising time on radio station WKDA.Four thousand different listeners heard its radio spots six times during a four-week period,and another 2,000 heard the commercial three times during the same four-week period.Calculate the average frequency.

A) 1
B) 2
C) 5
D) 6
E) 9