Ans: C

1. 
   

   Let the mass of block X and block Y be Xm and Ym respectively.
   the specific capacity of block X Xc and Yc respectively

   
   


2. 
   

   By Law of conversation of energy,
   Energy gained by block Y = Energy loss by block X

   
   

$m_{Y}c_{Y}(40-T)=m_{X}c_{X}(40-T)$

$c_{Y}(T=30)=c_{X}(40-T)$

3. Since
   $c_{X} > $c_{Y}$ and so T − 30 < 40 − T
   gives T > 35 degree Celsius.