For the month of September, Florida, Inc., incurs a direct materials cost of $12,000 for 7,500 gallons of strawberry lemonade produced in its Mixing Department. It also incurs conversion costs of $6,000 with 80% completed. If the direct materials cost per equivalent unit was $0.90 in August and the conversion cost per equivalent unit was $1.15 per gallon in August, what is the difference in the direct materials cost per equivalent unit between the two months?

a.$1.60

b.$0.10

c.$1.00

d.$1.15