Explanation:

- Option 1: Daman and Diu had a population of around 242,911 according to the 2011 Census. It was not the least populated among the union territories.

- Option 2: Delhi is a heavily populated region with a population of over 16 million in 2011.

- Option 3: Chandigarh had a population of approximately 1,055,450, according to the 2011 Census. It was not the smallest in terms of population.

- Option 4: Lakshadweep had the lowest population among the union territories listed, with a population of about 64,429 as per Census 2011.

- Option 4: Lakshadweep is correct.