John Lives in an Apartment Building and Gets a $700

Multiple Choice

John lives in an apartment building and gets a $700 benefit from playing his stereo.Mary,who lives next door to John and often loses sleep due to the music coming from John's stereo,bears a $1,000 cost from the noise.At which of the following offers from Mary could both Mary and John benefit from the silencing of John's stereo?

A) $200
B) $600
C) $900
D) $1,100