$1)$ What is a callable bond?

$2)$ What is the call price?

$3)$ How do you verify the call price of $101?$ What source document$($s$)$ do you need to obtain to verify the call price?

$4)$ How do you decide whether there is a gain or a loss from the bonds$$ early retirement?

$5)$ How do you verify the carrying value of the bonds at the early retirement?

$6)$ Which file $($a transaction file or a master file$)$ do you need to verify the cash paid for the early retirement? Be specific with your answer.