In the Gianni Cosmetics and Lube & Auto merger, what will be the yield associated with debt of combined firm if correlation of cash flows of Gianni & Lube is $1?$

Group of answer choices

$10\mathrm{.}5\%$

$11\mathrm{.}75\%$

$12\mathrm{.}71\%$

$14\mathrm{.}3\%$