One end of a long metallic wire of length L is tied to the ceiling. The other end is tied to massless spring of spring constant K. A mass m hangs freely from the free end of the spring. The area of cross-section and Young's modulus of the wire are A and Y respectively. If the mass is slightly pulled down and released, it will oscillate with a time period T equal to [IIT 1993]

• A.            \[2\pi \left( \frac{m}{K} \right)\]                                     
• B.            \[2\pi {{\left\{ \frac{(YA+KL)m}{YAK} \right\}}^{1/2}}\]
• C.            \[2\pi \frac{mYA}{KL}\]   
• D.            \[2\pi \frac{mL}{YA}\]