One end of a long metallic wire of length $L$ is tied to the ceiling. The other end is tied to a 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

• A
  $2\pi \sqrt{\frac{m}{K}}$
• B
  $2\pi \sqrt{\frac{(YA + KL)m}{YAK}}$
• C
  $2\pi \frac{mYA}{KL}$
• D
  $2\pi \frac{mL}{YA}$