The given graph represents the variation of Z\[\left(compressibility factor=\frac{PV}{nRT}\right)\]        versus P, for three real gases A, B and C. Identify the only incorrect statement

a) For the gas A, a = 0 and its dependence on P is linear at all pressure
b) For the gas B, b = 0 and its dependence on P is linear at all pressure
c) For the gas C, which is typical real gas for which neither a nor b = 0. By knowing the minima and the point of intersection, with Z = 1, a and b can be calculated
d) At high pressure, the slope is positive for all real gases

Answer: b
Explanation: For the gas B, b = 0 and its dependence on P is linear at all pressure