The correct option is D Cl2>Br2>F2>I2
The order of bond dissociation enthalpy is :
Cl2>Br2>F2>I2
As you go down the group the bond dissociation enthalpy should decrease, the only anomaly being Fluorine due to its small size.
Two fluorine atoms must come together to share a pair, but these many electrons concentrated on two small nuclei and separated over comparatively a very small distance repel each other.