Step 1: Understanding the Concept:
Low girl enrollment in many areas is driven by family and community attitudes, not only by school-level factors. So the most effective activity is one that changes attitudes at a wide scale.
Step 2: Why option A is correct.
An awareness campaign reaches parents, communities, and children together, changing the mindset that blocks girls from attending or continuing school. This addresses the root cause, not just the symptom.
Step 3: Why the other options are wrong.
Only school teaching helps girls already enrolled but does nothing for those kept out of school by family attitude. Fee change removes one barrier but leaves social resistance untouched. Integration of schools is an administrative step and does not by itself convince families to send daughters to school.
Final Answer:
An awareness campaign is the most suitable activity. This corresponds to option (A).