Serene Dairy Has Four Product Lines: Sour Cream, Ice Cream

Serene Dairy has four product lines: sour cream, ice cream, yogurt, and butter.The total cost of producing the milk base for the products is $45,000, which has been allocated based on the gallons of milk base used by each product.Results for July follow: $\begin{array}{lrrrrr}&\text {Sour Cream}&\text {Ice Cream}&\text {Yogurt}&\text {Butter}&\text {Total}\\\hline\text { Units sold } & 2,000 & 500 & 400 & 2,000 & 4,900 \\\text { Revenue } & \$ 10,000 & \$ 20,000 & \$ 10,000 & \$ 20,000 & \$ 60,000 \\\text { Variable departmental costs } & 6,000 & 13,000 & 4,200 & 4,800 & 28,000 \\\text { Fixed costs } & 5,000 & 2,000 & 3,000 & 7,000 & 17,000 \\\text { Net income (loss) }&\$(1,000) &\$5,000&\$2,800&\$8,200&\$15,000\end{array}$ How much are total joint costs of the products?

A) $28,000
B) $17,000
C) $45,000
D) $15,000