Answer: option A
Explanation: In simple words, competitive market refers to the market structure in which large number of buyers and sellers are present each operating at a small level and selling similar production with no interdependence on one another.
In such a structure, the sellers has to accept the price that is determined by the market forces of supply and demand as no individual participant can influence the price by changing output due to low level of operations.
Thus, the correct option is A.