Ron Moss, a manager of Waterworks, inc., was reviewing the water bills of a dog daycare and spa. He determined that its highest and lowest bills of $3,600 and s2,800 were incurred in the months of May and November, respectively. If 500 dogs were washed in May and 200 dogs were washed in November, what was the variable cost per dog associated with the company's water bili? (Round your answer to the nearest cent.) A) $4.00 B) $14.00 C) $7.20 D) $2.67