If all is held constant, it is expected that increase in the market demand for a product in a competitive market would result to an increase to the marginal cost (MC) curve of the firms.
An increase in market demand are caused by rise in income, rise in the price of a substitute, price fall of a complement product etc.
And when there is an increase in market demand, its reflects on the demand graph as the demand curve shift to the right.
Therefore, the Option E is correct.
Read more about market demand
brainly.com/question/3331860