In the simple economics of a competitive market price increases under which condition: a) Demand is constant

In the simple economics of a competitive market price increases under which condition:

a) Demand is constant. Supply declines: The supply curve shifts to the left, excess demand will occur at the initial price. Thus, the equilibrium price goes up.

b) Demand decreases. Supply increases: Under this scenario, the market price will decrease.

c) Demand and supply Rise concomitantly: The effect on price is unknown. If supply rises relatively more, then price falls. If demand rises relatively more, then the price rises.

d) Demand and supply Decline concomitantly: The effect on price is unknown. If supply falls relatively more, then price rises. If demand falls relatively more, then the price falls.

The answer is (A).