Maintenance costs at Seaside Manufacturing over the past six months are listed in the following table Month January February March April May June Maintenance cost $13,600 $14,720 $12,460 $14,480 $15,180 $13,200 Machine hours 15,500 16,900 13,900 16,600 17,500 15,000 O A. $1.32 O B. S0.76 OC. $087 O D. $0.90