The weighted average coupon of a bond, which is based on the following mortgages is closest to: Mortgage $x$ : value $-$$$1,900,000,$ time to maturity $27$ years, interest rate $5\mathrm{.}5\%$ Mortgage Y: value $-$$$1,150,000,$ time to maturity $-25$ years, interest rate $5\%$ Mortgage Z: value $-$$$1,850,000,$ time to maturity $-23$ years, interest rate $6\%$

$5\mathrm{.}57\%$

$6\mathrm{.}00\%$

$6\mathrm{.}23\%$

$5\mathrm{.}50\%$