Detailed Explanation:

Chandragupta II (Vikramaditya) assumed the Gupta throne by killing his elder brother Ramagupta, who had surrendered to the Shakas and dishonored the kingdom.

Samudragupta was his father and succeeded peacefully, Skandagupta later restored Gupta power against the Huns, and Shri Gupta was the dynasty's founder—none committed fratricide.

Therefore, Chandragupta II is the only Gupta ruler who killed his elder brother to seize power, making Option 2 the correct answer.