Explanation:

- Chandragupta I: He was an important king of the Gupta dynasty and laid the foundation of the Gupta Empire but did not assume the title of Vikramaditya.

- Chandragupta II:

- Assumed the title of Vikramaditya.

- Known as Chandragupta Vikramaditya.

- Expanded the Gupta Empire significantly.

- Samudragupta:

- Not associated with the title of Vikramaditya.

- Known for his military prowess and patronage of the arts.

- None of the above:

- Not applicable, as 'Chandragupta II' is the correct choice.