Consider the following production chain for a jersey. Assume that a Farmer shears sheep for wool, and sells this to a Miller for $7.00. The Miller spins thread, and sells this to a Manufacturer for $12.00. The Manufacturer makes a jersey, and sells this to a Retailer for $30.00 per jersey. The Retailer sells a jersey to a customer for $45.00. What is value added in the Manufacturer's industry?

a) $7.00

b) $5.00

c) $18.00

d) $15.00

which one, and why?