Variable costs as a percentage of sales for Lemon Inc. are $76\%,$ current sales are $$621,000,$ and fixed costs are $$175,000.$ How much will operating income change if sales increase by $$45,400?$

a$.$ $$34,504$ decrease

b$.$ $$10,896$ increase

c$.$ $$34,504$ increase

d$.$ $$10,896$ decrease