(4) For the following LP, 13 and 12 are basic variables in the optimal tableau. max z= 3x1 + 702 + 523 s.t. 11 + 12 +13 0 (a) Write the standard form. (b) Write all the related matrices or vectors IBV, INBV, CBV, CNBV, B, N and b and compute B-1. (c) For what ranges if just a changes, the current basis remains optimal? (d) For what ranges if just c2 changes, the current basis remains optimal? (e) For what ranges if just b changes, the current basis remains optimal