Alice is planning to open up a sandwich shop. An estimate of her costs$/$revenues are as follows: average sales price per sandwich: $$13\mathrm{.}75$; yearly rent: $$18,000$; monthly fixed utility bill: $$900$; average cost of ingredients per sandwich: $$4\mathrm{.}63$; monthly labour bill $($fixed$)$: $$11,500$; miscellaneous fixed supplies$/$month: $$250$; misc. variable supplies: $$2\mathrm{.}48$ per sandwich.

Her contribution margin per sandwich is

$$6\mathrm{.}64$

$$8\mathrm{.}48$

$$6\mathrm{.}00$

$$7\mathrm{.}42$