The correct answer is (c) Sulphuric acid.
Sulphuric acid is a strong acid that is used in car batteries to create a chemical reaction that produces electricity. The acid reacts with the lead plates in the battery to create lead sulfate, which is what stores the electricity. When the battery is discharged, the lead sulfate is converted back to lead and lead dioxide, which releases the electricity.
Sodium sulphate, nitric acid, and potassium nitrate are all electrolytes, but they are not used in car batteries. Sodium sulphate is a salt that is used in some industrial processes. Nitric acid is a strong acid that is used in some manufacturing processes. Potassium nitrate is a salt that is used in some fertilizers.
Sulphuric acid is the most common electrolyte used in car batteries because it is a strong acid that can produce a lot of electricity. It is also relatively inexpensive and easy to obtain.