The Relation PV = NRT Holds for All Ideal Gases

Multiple Choice

The relation PV = nRT holds for all ideal gases. The additional relation PVγ holds for an adiabatic process. The figure below shows two curves: one is an adiabat and one is an isotherm. Each starts at the same pressure and volume. Which statement is correct? (Note: "∝" means "is proportional to".)

A) Isotherm:
; Adiabat:
: A is both an isotherm and an adiabat.
B) Isotherm:
; Adiabat:
: B is an isotherm, A is an adiabat.
C) Isotherm:
; Adiabat:
: A is an isotherm, B is an adiabat.
D) Isotherm:
; Adiabat:
: B is both an isotherm and an adiabat.
E) cannot answer without additional information about the starting temperature.