Choose the word which is different from the rest.

The answer is B. Needle.

A stick is a long, thin piece of wood or other material. A needle is a long, thin piece of metal with a sharp point at one end and an eye at the other. A thorn is a sharp, pointed projection on a plant. A pin is a small, thin piece of metal with a head at one end and a sharp point at the other. A nail is a long, thin piece of metal with a head at one end and a sharp point at the other.

All of the options except needle are used to pierce or penetrate something. A needle is used to sew or knit.