The vertical axis of a demand curve shows the price of a product.
the supply of a produci.
the interest in a product.
the production cost of a product.

the price of a product.

Explanation:

The demand curve is the curve represented in the graph to show the relationship that exists between the price of the commodity and the demand of the commodity. According to the law of demand, with an increase in the price of a commodity, its demand decreases, and vice- versa. Usually, on the left vertical axis, the price of the commodity is marked and on the horizontal axis, the demand for the commodity is marked.

i thinl it is the 1st answer

the answer to this question is the third option. hope this