Two identical glass spheres filled with air are connected by a thin horizontal glass tube the glass tube contains a pellet of mercury at its mid-point Air in one sphere is at `0^(@)C` and the other is at `20^(@)C` if temperature of both the vessels are increased by `10^(@)C` then neglecting the expansions of the bulbs and the tube
A. the mercury pellet gets displaced towards the sphere at lower temperature
B. the mercury pellet gets displaced towards the sphere at higher temperature
C. the mercury pellet does not get displaced at all
D. the temperature rise causes the pellet to expand without any displacement
