The correct answer is C. Both 1 and 2.
Sodium sulphate and sodium silicate are added to detergents to improve their performance. Sodium sulphate helps to keep the detergent dry and free-flowing, while sodium silicate helps to maintain the alkalinity of the powder. This alkalinity is necessary to break down dirt and grease, and to help the detergent to dissolve in water.
Without sodium sulphate, the detergent would be more likely to clump together and become difficult to use. Without sodium silicate, the detergent would be less effective at cleaning clothes.
Therefore, both sodium sulphate and sodium silicate are important components of detergents.