In June, Blackfly Ltd. received a $5,000 cash payment for work billed the previous month. The company replanted a clear-cut area of northern Alberta for which it sent out an invoice for $20,000. At the beginning of the month the company had $1,000 of trees for planting. During the month the company purchased $4,000 more, and at the end of the month it was left with trees that had cost $500. The company's expenses were $1,000 in rent for its office and $3,000 in other expenses. Amortization on the truck and office equipment was calculated to be $500. The income tax rate is 10%. The gross profit as % of sales for the month was (accurate to one decimal place) Select one: O a. 10% Ob 25% c. 77.5% d. 80% e none of the above