The correct answer is: a) Present-day Pakistan.
The partition of India in 1947 led to the creation of two new countries: India and Pakistan. The border between the two countries was drawn through the Punjab region, which led to large-scale migration of people from one country to the other. Hindus and Sikhs from present-day Pakistan migrated to India, while Muslims from present-day India migrated to Pakistan. This migration was often violent and led to the deaths of millions of people.
Option b) is incorrect because Bangladesh was not created until 1971. Option c) is incorrect because Nepal and Bhutan are not located in the Punjab region. Option d) is incorrect because Afghanistan and Iran are not located in the Punjab region.