In the process of producing one hormone-free, stress-free, happy cow, the New Age Cattle Ranch produces one ton of natural, organic plant fertilizer. Demand for the ranch's cattle is given by Pc=2,000-10Qc, the demand for fertilizer is given by Pf=500-3Qf. The cost of producing Q cow-fertilizer bundles is C=5,000+300Q. To maximize profits, the ranch should:

a.produce 85 cow-fertilizer units; sell 85 cattle, and sell 33.33 tons of fertilizer.

b.produce 100 cow-fertilizer units; sell 100 cattle, and dispose of all the fertilizer in an environmentally friendly manner.

c.produce 85 cow-fertilizer units; sell 85 cattle, and sell 85 tons of fertilizer.

d.produce 85 cow-fertilizer units; sell 85 cattle, and sell 83.33 tons of fertilizer.

e.produce 84.62 cow-fertilizer units; sell 84.62 cattle, and sell 84.62 tons of fertilizer.

The correct answer is letter D. Can you show me how it was solved with explanations?