which of the following reasons explains the upward sloping of supply curve in a competitive market?

The reason that explains the upward sloping of the supply curve in a competitive market is that, ceteris paribus, marginal cost increases as output increases. This means that as firms produce more, they need to employ additional resources, such as labor and capital, which may not be as efficient as the resources they initially used. As a result, the additional units of output become more expensive to produce, and firms require a higher price to cover their costs and earn a profit. This relationship between marginal cost and output is reflected in the upward slope of the supply curve.