The "Syndicate" was a faction of senior Congress Party leaders who opposed Indira Gandhi's leadership due to her centralization of power. They were internal party figures, not external opposition. In contrast, the Grand Alliance comprised opposition parties from outside Congress, aiming to challenge Indira Gandhi.
Therefore, option (C) is incorrect because it misidentifies the Syndicate as opposition leaders, when they were indeed Congress leaders.
Consequently, the correct answer is (C) Syndicate – A group of powerful opposition leaders against Indira Gandhi.