A ten year callable bond with par value 1000 and annual coupons of 6%, has redemption value 1050 after 10 years, and is callable for 1050 after coupons are paid at end of years 6,7,8,9. The purchase price is 1025. At the end of which year (6,7,8,9,10) is the lowest annual yield going to occur? Give reasons. (You should not have to calculate the yields to determine the answer.)