An investor owns a municipal bond with a coupon rate of $4\mathrm{.}25\%.$ Assuming the annual inflation rate is $1\mathrm{.}65\%,$ calculate the investor's real rate of return on his bond.

$1\mathrm{.}58\%$

$4\mathrm{.}25\%$

$2\mathrm{.}56\%$

$2\mathrm{.}60\%$