Cascade Enterprises enjoys a substantial amount of market power in this market. Cascade has fixed costs of $2,000. Currently Cascade Enterprise employs eight workers to produce 430 units of output and, the last unit of worker contribute 40 units of output. If Cascade Enterprises pay a monthly wage rate of $2,000 and charge $50 per units for its product, what is the amount of profit made?
A. $3,500
B. $5,500
C. $ 60
D. $1,680