Use the Following to Answer Questions

Multiple Choice

Use the following to answer questions :
Scenario: Alexander and Vanessa
Alexander and Vanessa benefit from scientific research.Alexander's marginal private benefit from such research is given by the equation MPB = 200 - Q,where Q refers to the amount of research undertaken and MPB captures the marginal private benefit Alexander gets from different marginal quantities.Meanwhile,Vanessa's marginal private benefit from such research is given by the equation MPB = 100 - Q.The marginal social cost of such research is constant at $100.
-(Scenario: Alexander and Vanessa) Use Scenario: Alexander and Vanessa.If the socially optimal level of scientific research is produced and if both Vanessa and Alexander are truthful in disclosing the marginal private benefits they expect to receive from this research,what is the price per unit of research that Vanessa is willing to pay at the social optimum?

A) $0
B) $50
C) $100
D) $300