Which of the following bonds offers the highest current yield?

a$.$ A$($n$)3\mathrm{.}06\%,19-$year bond quoted at $45\mathrm{.}727.$

b$.$ A$($n$)5\mathrm{.}10\%,28-$year bond quoted at $76\mathrm{.}211.$

c$.$ A$($n$)1\mathrm{.}53\%,23-$year bond quoted at $22\mathrm{.}863.$

The current yield of the bond in part a is $\%.($Round to two decimal places.$)$