The scenario described involves the displacement of 17 million individuals due to the partition of India in 1947, which was a political and religious division of the region that led to violence and instability. Given this context, the most appropriate reason for migration in this case is:
• forced political migration
The partition created significant political and social upheaval, leading to the forced movement of people based on religious identity, resulting in widespread violence and the need for individuals to flee for safety.