Sarah went to the grocery store and bought 4 loaves of bread and 1 gallon of milk for $12. the next week, sarah bought 2 loaves of bread and 3 gallons of milk for $13.50. which system of equations below can be used to determine the cost of one loaf of bread (b) and one gallon of milk (m)? a. 4m × b = $12 2m × 3b = $13.50 b. 4b × m = $12 2b × 3m = $13.50 c. 4m + b = $12 2m + 3b = $13.50 d. 4b + m = $12 2b + 3m = $13.50