Which type of solute is present in aqueous solution predominantly as hydrated ions rather than as molecules?

Answer is: strong electrolyte.

Strong electrolytes better separates into particles (ions) in water because of their ionic bond.

For example sodium chloride is ionic compound and strong electrolyte and dissociates in water on hydrated sodium cations and chlorine anions:

NaCl (aq) → Na⁺ (aq) + Cl⁻ (aq).