The value of the WhatsApp Messenger to an individual user ...

[Caiter2013]

The value of the WhatsApp Messenger to an individual user increased as more of his friends and acquaintances started using it. This is an example of a(n) ________.
 
  A) moral hazard
  B) adverse selection
  C) network externality
  D) negative externality

Question 2

Roughly how many times has the U.S. experienced a budget surplus since 1960?
 
  A) 0
  B) 5
  C) 10
  D) 20
  E) 30

[ynlevi]

Answer to Question 1

C

Answer to Question 2

B

[Caiter2013]

Thanks for the timely response, appreciate it

[bitingbit]

Gracias!