Answer: Group of buyers and sellers
Explanation: A market refers to a place where the transactions of selling and purchasing takes place. In a market the person having a commodity willing to sell that, can meet with a number of prospective buyers and choose the one who best suits him.
It is a gathering of people having the resources that can satisfy each others wants. It is not mandatory to have a particular physical place but it necessary for a market to have participants in the form of buyer and seller to exist.
Hence the correct option is A.