In substitution type of questions, some particular objects are assigned code names. Then a question is asked that is to be answered in the code language.
If lead is called stick, stick is called nib, nib is called needle, needle is called rope and rope is called thread, what will be fitted in a pen to write with it ?
Clearly, a 'nib' is fitted in the pen to write with it.
But a 'nib' is called 'needle'.
So, a 'needle' will be fitted in the pen.