Concept:The Ombudsman investigates complaints but cannot enforce its own recommendations.
Explanation:The Ombudsman is meant to check administrative injustice and protect citizens from unfair official conduct.
It has the power to investigate complaints and recommend remedies.
However, it does not possess executive power to compel any authority to obey its decisions.
It can only report its findings and suggestions to the relevant body for action.
This lack of enforcement authority makes its decisions weak and non-binding.
Thus, the major shortcoming is its inability to enforce decisions.
Answer:D. lack of executive power to enforce decisions.