Mark the correct option:

Options

A. A system X is in thermal equililbrium with Y but not with Z. System Y and Z may be in thermal equilibrium with each other.
B. A system X is in thermal equlibrium with Y but not with Z. System Y and Z are not in thermal equilibrium with each other.
C. A system X is neither in thermal equilibrium with Y nor with Z. The system Y and Z must be in thermal equilibrium with each other.
D. A system X is neither in thermal equilibrium with Y nor with Z. The system Y and Z may be in thermal equilibrium with each other.

Answer

B, D

Explanation

If `T_(x)=T_(y)` and `T_(x) ne T_(z)`, then `T_(y) != T_(z)`.
If `T_(x) != T_(y)` and `T_(x) != T_(z)`, then `T_(y) != T_(z)` but `T_(y)` may be equal to `T_(z)`.