At very high pressures, the compressibility factor of one mole of a gas is given by:

• Correct answer
  A

  $1+\frac{\mathrm{P}\mathrm{b}}{\mathrm{R}\mathrm{T}}$
• B

  $\frac{\mathrm{P}\mathrm{b}}{\mathrm{R}\mathrm{T}}$
• C

  $1-\frac{\mathrm{P}\mathrm{b}}{\mathrm{R}\mathrm{T}}$
• D

  $1-\frac{\mathrm{b}}{\left(\mathrm{V}\mathrm{R}\mathrm{T}\right)}$

Hence, the correct answer is option: 'A'.