Answer:
Option D. NaOH, is the correct answer.
Explanation:
NaOH is an ionic compound which act as a base when dissolved in water. Sodium hydroxide is also called caustic soda. The bond between sodium and hydroxide is ionic. The charge on sodium is positive due to loss of one electron while charge on hydroxide is negative due to addition of electron. Its colour is white. It is present in solid form. It act as base due to the presence of OH ion.