Generally, you may expect ionization to be greater:
in dilute solutions
in 1 m solutions
in high concentration solutions
none of these

The correct statement is in dilute solutions.

Explanation:

Ionization is a process in which an electrolyte breaks into its ions when dissolved in water.

If the solution is dilute, which means more water molecules are present and they surround the oppositely charged ions more and hence, it will result in higher dissociation of electrolyte.

Therefore, the correct statement is in dilute solutions.