Equilibrium Price with Vertical Supply and Free Provision

Steps:

• Vertical supply curve fixes equilibrium quantity at the supplied amount.
• Equilibrium price occurs where demand curve intersects vertical supply line.
• This intersection point is labeled P on the demand curve.
• Free provision means consumers pay zero, but market equilibrium price remains P.

Why C is correct:

• With vertical supply, equilibrium price is determined by demand at fixed quantity (law of supply and demand), shown as P.

Why the others are wrong:

• A: Consumer surplus is determinate as area under demand curve up to quantity supplied, despite vertical supply.
• B: Vertical supply makes equilibrium price determinate via demand intersection, not indeterminate.
• D: Zero is consumer price due to free provision, but market equilibrium price is P from curves.

Final answer: C