(A) : Thermal expansion of solids is due to the anharmonicity of the lattice vibrations.
( R) : As the temperature of the solid increases, the amplitude of vibrating atoms increases.

Options

A. Both (A) and (R) are true and (R) is the correct explanation of (A)
B. Both (A) and (R) are true and (R) is not the correct explanation of (A)
C. (A) is true but (R) is false
D. Both (A) and (R) are false

Answer

B