The equation 40%(b + $20.00) = 40%(b) + $8.00 can be matched to the following situation:
C. The cost for a coat was 40% of the sum of b and $8.00.
This is because the left-hand side represents 40% of the total amount (b + $20.00), while the right-hand side splits it into two parts: 40% of b and an additional $8.00.