In producing a sweater, a man who shears sheep pays a farmer $4 for a sheep. The shearing shop sells the wool to a knitting mill for $7. The knitting mill buys the wool and makes it into a fine fabric and sells it to a sweater-making firm for $13. The sweater-making firm sells the sweater to a clothing store for $20, and the clothing store sells the sweater, gift wrapped, for $50. What is the contribution to GDP of the previous sales transactions?
1) $4
2) $44
3) $50
4) $94