The correct answer is option 4, Kalinga. In the pre-Mauryan period, the sixteen mahajana-padas were the major political and cultural centers of ancient India. These mahajana-padas were powerful and influential kingdoms of the time. The options listed in the question are all examples of mahajana-padas, except for Kalinga.

Option 1, Kuru, refers to the ancient kingdom located in the northern parts of present-day India. It was one of the dominant mahajana-padas and played an important role in the development of early Indian civilization.

Option 2, Vatsa, was another significant mahajana-pada known for its capital, Kaushambi. It was situated in the northern part of present-day Uttar Pradesh and had close ties with the Magadha Kingdom.

Option 3, Gandhara, was a mahajana-pada located in the northwest region of ancient India, covering parts of present-day Pakistan and Afghanistan. Gandhara had strong cultural and trade connections with other mahajana-padas and played a crucial role in facilitating cultural exchange between India and Central Asia.

It is important to note that Kalinga, which is option 4, was not one of the sixteen