The necessary and sufficient condition for the existence of a feasible solution to the transportation problem is

A. number of rows should be equal to the number of columns

B. the total destination requirement equals the total origin capacity, $$\sum\limits_{i = 1}^m {{a_i}} = \sum\limits_{j = 1}^n {{b_j}} $$

C. the total destination requirement is not equal to the total origin capacity, $$\sum\limits_{i = 1}^m {{a_i}} \ne \sum\limits_{j = 1}^n {{b_j}} $$

D. the total destination requirement is more than the total origin capacity

Answer: Option B