Evans Engineering$$s product component average unit cost is $$26,$ comprised of $$10$ in direct materials, $$7$ in direct labor, and $$9$ in overhead, of which $$1$ is variable. Evans has received an offer from an outside supplier who could produce the component part for a unit price of $$21.$ If Evans purchases the component from the outside supplier, they could eliminate $75\%$ of fixed overhead. The per$-$unit impact of purchasing from the outside supplier is $($show work$)$:

a$.$ $$1$ disadvantage

b$.$ $$5$ advantage

c$.$ $$3$ advantage

d$.$ $$4$ disadvantage