The following table summarizes the yields to maturity on several one$-$year, zero$-$coupon securities$.$

$\backslash$table$[[$Security$,$Yield $(\%)],[$Government of Canada,$3\mathrm{.}11],[$AAA corporate,$3\mathrm{.}26],[$BBB corporate,$4\mathrm{.}25],[$B corporate,$4\mathrm{.}93]]$

a$.$ What is the price $($expressed as a percentage of the face value$)$ of a one$-$year, zero$-$coupon corporate bond with an AAA rating?

b$.$ What is the credit spread on AAA$-$rated corporate bonds?

c$.$ What is the credit spread on B$-$rated corporate bonds?

d$.$ How does the credit spread change with the bond rating? Why?