Explanation:

- Monopolistic competition features a variety of elements that distinguish it from other market structures.

- Option 1: Large number of buyers and sellers in the market. - This is a common feature of monopolistic competition, as many sellers offer similar but not identical products.

- Option 2: Differentiated products constitute the market. - True for monopolistic competition, products are differentiated to attract different consumer segments.

- Option 3: Product in the market is homogeneous. - Correct. This is not a feature of monopolistic competition, as the market is characterized by product differentiation rather than homogeneity.

- Option 4: Selling costs are used for sale promotion. - A feature of monopolistic competition, where companies spend on advertising to maintain their unique product identity.