1- An optimization model must decide how to allocate available supplies si at sources i=1,,m to meet requirements rj at customers j=1,,n. Using decision at variables wi,j: amount allocated from source i to customer j formulate each of the following requirements(constraints) in a single line (hint: use summation sign, for all/each notation where necessary). a. The amount allocated from source 32 cannot exceed the supply available at 32. b. The amount allocated from each source i cannot exceed the supply available at i. c. The amount allocated to customer n should equal the requirement at n. d. The amount allocated to each customer j should equal the requirement at j