Determine the Physical State of A Substance at a Given Temperature

SPM 2012 Paper 1 Question 25  

1. The melting point and boiling point of  V and W are lower than 100⁰C. Both exist as solid at 100⁰C. 
2. The melting point of  X is lower than 100⁰C. The boiling point of X is higher than 100⁰C.  It exists as liquid in room temperature.
3. Both the melting point and boiling point of Y are lower than 100⁰C.  It exists as gas in room 100⁰C. 

The correct answer is : C