Explanation:

Let’s break it down:

- Option 1: Agra — It’s a famous city, but Tansen wasn’t born here. He later performed at Akbar’s court in Agra, though.

- Option 2: Chanderi — Some old sources suggest Chanderi, but this isn’t widely accepted. It’s debated but not the mainstream view.

- Option 3: Delhi — This is just not correct. Tansen worked for the Mughal Emperor but wasn’t born in Delhi.

- Option 4: Gwalior — Gwalior is the widely accepted birthplace of Tansen. Most historians agree on this. His early musical training also happened here.

So, the correct answer is Option 4: Gwalior.