The correct answer is C. Many buyers and many sellers.
Perfect competition is a market structure in which there are many buyers and sellers of a homogeneous product, and no one buyer or seller has a significant impact on the market price. In a perfectly competitive market, buyers and sellers have perfect information about the product and the market, and there are no barriers to entry or exit.
Option A is incorrect because a market with few buyers and few sellers is a monopoly. A monopoly is a market structure in which there is only one seller of a good or service.
Option B is incorrect because a market with many buyers and few sellers is an oligopoly. An oligopoly is a market structure in which there are a few large sellers of a good or service.
Option D is incorrect because honesty is not an assumption of perfect competition. In a perfectly competitive market, buyers and sellers are assumed to be rational and self-interested, but there is no assumption that they are honest.