John Receives a Marginal Benefit of $80 from One Satellite

John receives a marginal benefit of $80 from one satellite.Nick receives a marginal benefit of $50 from one satellite.Christina receives a marginal benefit of $65 from one satellite.John,Nick,and Christina are the only people in the economy What is the economy's marginal social benefit from one satellite?

A) $30
B) $195
C) $15
D) $80
E) $65