Gold number is [MP PET/PMT 1988]

• A. The number of mg of lyophilic colloid which should be added to 10 ml of ferric hydroxide sol so as to prevent its coagulation by the addition of 1 ml of 10% sodium chloride solution
• B. The number of mg of lyophilic colloid which should be added to 10 ml of standard gold sol so as to prevent its coagulation by the addition of 1 ml of 10% NaCl
• C. The mg of gold salt to be added to a lyophilic colloid to coagulate it
• D. The mg of an electrolyte required to coagulate a colloid