$18.$ Contribution Margin Concepts DiPinto Electric Guitars $\backslash$& Basses sells musical instruments in Philadelphia. Assume the following information comes from the company's prior year records. REQUIRED a$.$ Determine the annual break$-$even dollar sales volume. b$.$ Determine the current margin of safety in dollars. c$.$ Prepare a cost$-$volume$-$profit graph for the guitar shop. Label both axes in dollars with maximum values of $\backslash (\backslash$$ $1,000,000\backslash ).$ Draw a vertical line on the graph for the current $\backslash ((\backslash$$ $800,000)\backslash )$ sales level, and label total variable costs, total fixed costs, and total profits at $\backslash (\backslash$$ $800,000\backslash )$ sales. d$.$ What is the annual break$-$even dollar sales volume if management makes a decision that increases fixed costs by $\backslash (\backslash$$ $50,000\backslash )?$