Normally a demand curve will have the shape

The correct answer is C. Downward sloping.

A demand curve is a graph that shows the relationship between the price of a good and the quantity demanded of that good. The demand curve is downward sloping because, in general, consumers are willing to buy more of a good when the price is lower.

A horizontal demand curve would mean that consumers are willing to buy the same quantity of a good regardless of the price. This is not realistic, as consumers are generally willing to buy more of a good when the price is lower.

A vertical demand curve would mean that consumers are only willing to buy a certain quantity of a good, regardless of the price. This is also not realistic, as consumers are generally willing to buy more of a good when the price is lower.

An upward sloping demand curve would mean that consumers are willing to buy less of a good when the price is lower. This is not realistic, as consumers are generally willing to buy more of a good when the price is lower.