Sun Brite has a new pair of sunglasses it is evaluating, The company expects to sell $6,700$ pairs of sunglasses at a price of $$162$ each and a variable cost of $$114$ each. The equipment necessary for the project will cost $$350,000$ and will be depreciated on a straight$-$line basis over the $6-$year life of the project. Fixed costs are $$280,000$ per year and the tax rate is $21\%.$ How sensitive is the operating cash flow to a $$1$ increase in variable cost per pairs of sunglasses?

$1.-3,618$

$2.-5,293$

$3.-4,467$

$4.-3,618$

$5.-4,020$