Four different experiments were conducted in the following ways : I. 3 g of carbon was burnt in 8 g of oxygen to give 11 g of \[\text{C}{{\text{O}}_{\text{2}}}\]. II. 1.2 g of carbon was burnt in air to give 4.2 g of \[\text{C}{{\text{O}}_{\text{2}}}\]. III. 4.5 g of carbon was burnt in enough air to give 11 g of \[\text{C}{{\text{O}}_{\text{2}}}\]. IV. 4 g of carbon was burnt in oxygen to form 30.3 g of \[\text{C}{{\text{O}}_{\text{2}}}\]. Law of constant proportions is illustrated in experiment(s)

• A. I and III     
• B. II and III 
• C. IV only
• D.        I only.