Explanation:

Ionization Energy:
Ionization energy is the energy required to remove an electron from an atom or ion in the gaseous state. It is expressed in units of kilojoules per mole (kJ/mol). The higher the ionization energy, the more difficult it is to remove an electron from an atom or ion.

Hydration Enthalpy:
Hydration enthalpy is the enthalpy change that occurs when one mole of gaseous ions is dissolved in water to form aqueous ions. It is expressed in units of kilojoules per mole (kJ/mol). The higher the hydration enthalpy, the more favorable the process of dissolving ions in water.

Electron Affinity:
Electron affinity is the energy change that occurs when an atom or ion in the gaseous state gains an electron to form a negative ion. It is expressed in units of kilojoules per mole (kJ/mol). The higher the electron affinity, the more favorable the process of gaining an electron.

Electronegativity:
Electronegativity is a measure of the tendency of an atom to attract a shared pair of electrons towards itself when it is participating in a covalent bond. It is a dimensionless quantity. The higher the electronegativity, the more strongly an atom attracts electrons towards itself.

Explanation of the correct answer:

The correct answer is option 'B' - "Cl has lower hydration enthalpy."

Hydration enthalpy:
When an atom or ion is dissolved in water, it interacts with water molecules through ion-dipole interactions. The energy released when these interactions occur is called hydration enthalpy. Hydrogen, being a small atom, can easily form strong ion-dipole interactions with water molecules, resulting in the formation of H+ (aq) ions. On the other hand, chlorine, being a larger atom, has a lower ability to form strong ion-dipole interactions with water molecules. Therefore, chlorine does not form Cl- (aq) ions easily.

Comparison of ionization energy:
The ionization energy of hydrogen is 1311 kJ/mol, while the ionization energy of chlorine is 1256 kJ/mol. These values indicate that it is easier to remove an electron from a chlorine atom than from a hydrogen atom. However, the formation of ions in water depends not only on the ionization energy but also on the hydration enthalpy.

Conclusion:
Based on the given information, the correct answer is option 'B' - "Cl has lower hydration enthalpy." Chlorine does not form Cl- (aq) ions easily because it has a lower ability to form strong ion-dipole interactions with water molecules compared to hydrogen.

Hydration energy of Cl⁺ is very less than H⁺ hence it doesn’t form Cl⁺ (aq) ion.