A Certain Commodity Has Demand Curve P = $\frac { 20 } { x + 5 }$

Multiple Choice

A certain commodity has demand curve p = $\frac { 20 } { x + 5 }$ - 1 at sales level x. What is the consumers' surplus if 5 units are currently being sold?

A) 20(ln 10) - 10
B) 20(ln 15 - ln 5) - 10
C) 20(ln 15 + ln 5) - 10
D) $\frac { 1 } { 20 }$ (ln 3) - 20
E) none of these