13. Beach Time produces two models of beach chairs, Lay Back and Easy Rest. Information regarding these products for May follows: Lay Back Easy Rest Number of units 6,000 14,000 Sales revenue $120,000 $140,000 Fixed costs 24,000 50,000 Variable costs 60,000 42,000 Prot M M Selling price per unit $20 $10 How much is Beach Time's weighted average contribution margin ratio? A) 60.00% B) 32.3 1% C) 60.77% D) 71.53%