Van der Waals derived an expression for the 'pressure defect', if the observed pressure is denoted as 'p' and volume is denoted as 'V', the gas pressure in the bulk of the gas is equal to:

• A. p + a⁄(V²); where a: constant for the particular gas
• B. p + a⁄V; where a: constant for the particular gas
• C. p + (a × V²); where a: constant for the particular gas
• D. p + (a × V); where a: constant for the particular gas