The positive relationship between quantity supplied and the market price along a supply curve may be explained?

[helghan]

a. rising marginal costs of production
b. the Law of Diminishing Marginal Utility
c. negative externalities
d. the fact that private and social marginal cost may not coincide

[alex v]

B) Due to the law of diminishing marginal utility in a nut shell relating to supply means that price and quantity supplied is directly related, meaning the profit return is higher as more is supplied as more is sold.
Hope this helps!