For a firm that would break even at $200 000 sales and earn a profit of $30 000 at sales of $250 000, which ollowing statements is always true? Select one: Oa. The contribution margin is 60 per cent of sales. Ob. The selling price is $2 per unit. Oc. Fixed costs are $80 000. d. Profit at sales of $300 000 would be $80.000.