Three masses 700g, 500g, and 400g are suspended at the end of a spring a shown and are in equilibrium. When the 700g mass is removed, the system oscillates with a period of 3 seconds, when the 500 gm mass is also removed, it will oscillate with a period of

• A.            1 s
• B.            2 s
• C.            3 s 
• D.            \[\sqrt{\frac{12}{5}}\,s\]