Suppose We Observe an Increase in Both the Equilibrium Price

Suppose we observe an increase in both the equilibrium price and quantity of bread. This is best explained by:

A) an increase in the cost of flour used in the production of bread.
B) a technological advance that lowers the marginal cost of producing bread.
C) a decrease in the price of butter, a complement to bread.
D) a decrease in the price of pasta, a substitute to bread.