Answer:
D. The equilibrium price and quantity increases
Step-by-step explanation:
When the demand curve shifts to the right and the supply curve is held constant, the equilibrium price and quantity increases.
A rightward shift in the demand curve from D1 to D2 an a supply curve S held constant, the equilibrium price increases from P1 to P2 and equilibrium quantity increases from Q1 to Q2.
Therefore, a shift in demand curve to the right at a constant supply curve will increase equilibrium price and quantity.
See graph attached for more information