The following data relate to a company that produces and sells a travel guide that is updated monthly Fixed costs: Copy editing $ 6,000 Art work $2,000 Typesetting $ 72,000 Variable costs $3.20 per Printing and binding copy $4.00 per Bookstore discounts copy Salespersons $0.50 per commissions copy $2.00 per Author's royalties copy Each book sells for $ 20.00. The company sold 8,000 books in June and 10,000 books in July. WHAT IS THE CONTRIBUTION MARGIN RATIO ?

A. 51.9%, B. 54.0%, C. 71.5%, D. 51.5%