The city of Lahore, once a cultural and economic center of Punjab, became part of:

India
Pakistan
An independent state
A disputed territory

The correct answer is: b) Pakistan.

Lahore is the capital of the Pakistani province of Punjab. It is the second most populous city in Pakistan after Karachi. Lahore is a major cultural and economic center of Pakistan. The city is home to many historical and cultural sites, including the Lahore Fort, the Badshahi Mosque, and the Shalimar Gardens. Lahore is also a major commercial and industrial center. The city is home to many factories and businesses.

Lahore was once part of the Indian subcontinent. After the partition of India in 1947, Lahore became part of Pakistan. The city has been a major center of Pakistani culture and politics since then.

The other options are incorrect. Option a) is incorrect because Lahore is not part of India. Option c) is incorrect because Lahore is not an independent state. Option d) is incorrect because Lahore is not a disputed territory.