A machine of mass 100 kg is subjected to an external harmonic force with a frequency of 40 rad/s. The designer decides to mount the machine on an isolator to reduce the force transmitted to the foundation. The isolator can be considered as a combination of stiffness (K) and damper (damping factor, ζ) in parallel. The designer has the following four isolators :

1) k = 640 kN/m, ζ = 0.70

2) k = 640 kN/m, ζ = 0.07

3) k = 22.5 kN/m, ζ = 0.70

4) k = 22.5 kN/m, ζ = 0.07

Arrange the isolators in the ascending order of the force transmitted to the foundation.