Three blocks of masses `m_(1),m_(2)`and `m_(3)` are connected by massless strings as shown on a frictionless table. They are pulled with a force `T_(3)=40N`. If `m_(1)=10kg,m_(2)=6kg` and `m_(3)=4kg` the tension `T_(2)` will be
A. 20 N
B. 40 N
C. 10 N
D. 32 N
