The Figure Shows the Supply Curve (S) and the Demand

Multiple Choice

The figure shows the supply curve (S) and the demand curve (D) for college education. The external benefit from college education is $6,000 per student per year and is constant.
-In the figure above, if the government gives a voucher equal to $3,000 per year to each college student, how many students will be accepted?

A) 8 million per year
B) 12 million per year
C) 10 million per year
D) 14 million per year