The time complexity of Ford - Fulkerson algorithm is θ ( |E| * |f|), which one the following is the best explanation for getting this complexity

a. the cost of finding the augment path is θ (E), and in worst case finding one path that add one flow unit to current flow
b. at each step the algorithm check current flow values at each edge in order to find the amount of flow units that can flow in the graph
c. because algorithm update each value in the graph flow every time we find a new augmenting path