$($Advanced analysis$)$ The demand for commodity $x$ is represented by the equation $P=10-0\mathrm{.}2Q$ and supply by the equation $P=2+0\mathrm{.}2Q.$ If demand changes from $P=10-0\mathrm{.}2Q$ to $P=7-0\mathrm{.}3Q,$ the new equilibrium price is

Multiple Choice

$$2.$

$$6.$

$$7.$

$$4.$