A fluid gas produced on burning furnace oil contains $0\mathrm{.}15$ gm mole of CO$2,0\mathrm{.}05$ gm mole of oxygen and $0\mathrm{.}80$ gm mole of N$2.$ What is its molecular weight?

$28\mathrm{.}6$

$30$

$30\mathrm{.}6$

$32\mathrm{.}6$