Martin was a professional classical guitar player until a motorcycle accident left him disabled. After long months of therapy, he hired an experienced luthier and started a small shop to make and sell Spanish guitars. The guitars sell for $700, and the fixed monthly operating costs are as follows Rent and utilities Wages and benefits to luthier Other expenses $700 2,300 481 Martin's accountant told him about contribution margin ratios, and Martin understood clearly that for every dollar of sales, $0.60 went to cover his fixed costs, and anything above that point was profit. Martin wishes to earn $4,000 of operating profit each month. Calculate the number of guitars Martin will need to sell to achieve the target profit. (Round your answer up to the nearest whole guitar.) OA. 5 guitars O B. 4 guitars C. 18 guitars O D. 17 guitars