An investor purchases a $12-$year, $6\mathrm{.}9\%$ annual coupon payment bond at a price equal to par

value. After the bond is purchased and before the first coupon is received, interest rates increase

by $0\mathrm{.}5\%.$ The investor sells the bond after $7$ years, Assume that interest rates remain unchanged at $6\mathrm{.}9+0\mathrm{.}5\%$ over the $7-$year holding period.

Assuming that all coupons are reinvested over the holding period, what is the investor's $7-$year horizon yield?

$(1)$