An artist is creating a gigantic mobile using old cars. On one end of the mobile, a 2100 lb Plymoth is suspended 30 feet from the fulcrum. In order for the mobile to be balanced, where should the artist suspend a 1400 lb Volkswagon?

a
20 feet from the fulcrum

b
7 feet from the fulcrum

c
45 feet from the fulcrum

d
on the fulcrum