Using the following actual callable bond trade record,

Interest rate. Bond price. Pvbp$.$ Duration

$6\%.$ $$99\mathrm{.}50$

$5\mathrm{.}85\%.$ $$99\mathrm{.}83.$ A

$5\mathrm{.}75\%.$ $$100\mathrm{.}72$ B

$5\mathrm{.}5\%.$ $$101\mathrm{.}86$

A$)$ show the process and compute the pvbp at point A

B$)$ show the process and compute the duration at point B