Vessels A and B are made of conducting material. Both contain water. Vessel A floats in B. Vessel B is now heated at a uniform rate, then a) Water in A boils first b) Water in A boils some time after water in B starts boiling c) Water in both A and B starts boiling simultaneously d) Water in A does not boil
Well logically I tried and got the answer as b) but apparently the correct option is a). I think that it may be possible that all the thermal energy being obtained by the water in B is conducted (whether by conduction or convection) to the water and A and hence the temperature remains more or less the same. But after some time when the water in A has reached a certain point after which it starts boiling, there is no other place for the thermal energy to go (it can't escape into the atmosphere since it is a comparatively worse conductor than water) and therefore the water in B starts boiling after A.
But I'm unable to put forward a concrete logic supported by scientific evidence. Any help would be appreciated.
(I apologise for the improper use of the tags as I'm unclear about the tags to be used.)