Suppose the APT has two factors. The expected returns on the first and second factors are $12\%$ and $10\%,$ respectively. Stock ACM has a beta of $1\mathrm{.}4$ on factor $1$ and a beta of $0\mathrm{.}6$ on factor $2.$ The expected return on ACM is $16\mathrm{.}3\%.$ Based on the APT, what is the risk$-$free rate?

A$.8\mathrm{.}2\%$

B$.6\mathrm{.}5\%$

C$.5\mathrm{.}4\%$

D$.7\mathrm{.}2\%$