A Ten-Year Bond Was Issued in 2013 at a Discount

A ten-year bond was issued in 2013 at a discount with a call provision to retire the bonds. When the bond issuer exercised the call provision on an interest date in 2015, the carrying amount of the bond was less than the call price. The amount of bond liability removed from the accounts in 2015 should have equaled the

A) call price.
B) call price less unamortized discount.
C) face amount less unamortized discount.
D) face amount plus unamortized discount.