Which of the following king assumed the title of 'Maharajadhiraj'?

The correct answer is Option 4- Chandragupta I

The first king to assume the title of "Maharajadhiraj" was Chandragupta I, the founder of the Gupta dynasty.

The title "Maharajadhiraj" means "king of kings" in Sanskrit. It is a title that was used by the most powerful rulers in India.

Chandragupta I was a very powerful ruler, and he expanded the Gupta Empire to include a large part of North India. He also forged alliances with other powerful dynasties, such as the Vakatakas and the Kadambas.

Chandragupta I's assumption of the title "Maharajadhiraj" was a sign of his power and prestige. It was also a way for him to assert his dominance over other rulers in India.