Someone please answer this question in detail, I have an examp in 1 hr!! Especially part B and C.

Suppose a company manufactures two products, A and B, using three inputs, labor, material R, and materials S. To make one unit of product A requires 6 pounds of R,7 pounds of S, and 9 person-hours of labor; to make one unit of product B requires 12 pounds of R,4 pounds of S, and 6 person-hours of labor. The demands for the products are such that the company can sell as much of each product as it can produce and earn a profit of \$3 per unit of A and \$4 per unit of B. However, only 900 pounds of R, 675 pounds of S, and 1200 person-hours of labor are available to the company each day. The computer solution of the problem is given below. VariableCells Constraint s Page 2 of 3 2/3 6mp203 (A) Formulate a linear programming model for this problem. What is the optimal product mix and the corresponding maximum profit? (B) What is the optimality range for the per unit contribution of each product? (C) Write the shadow price and range for each resource where shadow price is applicable. (D) Write the dual of above LP problem formulated in part(a). [20]