A company sells two models of a product$-$basic and premium. If the company $5$ ells $5,000$ basic models and $2,500$ premium models, then the sales mix can be expressed as:

$5\mathrm{.}7\mathrm{.}5.$

$5\mathrm{.}2\mathrm{.}5.$

$2$:$1.$

$3$:$2.$