A transport company operates two type of trucks of 60 cubic meters capacity. Type A trucks each have a refrigerated capacity of 20 cubic meters and a non-refrigerated capacity of 40 cubic meters. Type B trucks on the other hand, are equally split with refrigerated, and non-refrigerated capacities of 30 cubic meters. A grocer needs to hire trucks for the transport of at least 3,000 cubic meters of refrigerated stock and at least 4000 cubic meters of non-refrigerated stock. The cost per kilometer of a Type A truck is $30, and $40 for a Type B truck. Formulate the cost optimization problem for the grocer in terms of the following decision variables: X: number of Type A trucks to hire X: number of Type B trucks to hire A. B. min 30xa + 40X, subject to: 20X + 40x, >= 3000; 30X + 30X >= 4000; X, Xb >= 0; X, X are integers D. max 30X + 40X subject to: 20X + 40X >= 3000; 30Xa + 30X >= 4000; Xa. Xb >= 0; Xa. Xb are integers min 30X + 40X, subject to: 20X + 30X >= 3000; 40X + 30X >= 4000; X, X >= 0; X, X are integers C. max 30X + 40X subject to: 20X + 30X >= 3000; 40Xa + 30Xb>= 4000; Xa: Xb>= 0; Xa Xb are integers