In the Figure,an Airport Luggage-Carrying Train with a Tractor T

Multiple Choice

In the figure,an airport luggage-carrying train with a tractor T is pulling three luggage carts,M₁,M₂,and M₃ with an acceleration of 1.2 m/s².If T = 300 kg,M₁ = 200 kg,M₂ = 100 kg,and M₃ = 100 kg,then the force in the connection between cart M₂ and cart M₁ is

A) 840 N.
B) 480 N.
C) 240 N.
D) 120 N.
E) 0 N.