Kim Airedale, a manager of Waggers, Inc., was reviewing the water bills of a dog daycare and spa. She determined that its highest and lowest bills of $3,400 and $2,800 were incurred in the months of May and November, respectively. If 600 dogs were washed in May and 100 dogs were washed in November, what was the variable cost per dog associated with the company's waterbill? (Round your answer to the nearest cent.) OA. $5.67 O B. $4.00 O C. $28.00 O D. $1.20