Three Identical Springs (X, Y, Z)are Arranged as Shown

Multiple Choice

Three identical springs (X, Y, Z) are arranged as shown.When a 4.0-kg mass is hung on X, the mass descends 3.0 cm.When a 6.0-kg mass is hung on Y, the mass descends:

A) 2.0 cm
B) 4.0 cm
C) 4.5 cm
D) 6.0 cm
E) 9.0 cm