Which one of the following leaders of the Congress was totally in favour of Cabinet Mission Plan ?

Among the top Congress leadership, Sardar Vallabhbhai Patel was the most resolute supporter of the Cabinet Mission Plan of 1946. His stance was based on several key factors:

• Prevention of Partition: Patel saw the plan as the only way to keep India united and avoid the creation of a separate Pakistan.
• Pragmatism: Unlike Gandhi, who was suspicious of the 'grouping' of provinces, or Nehru, who wanted the Constituent Assembly to be completely unfettered, Patel believed Congress should accept the plan to gain control of the Interim Government.
• Political Strategy: He argued that once the Congress was in power at the center, it could effectively manage the administrative challenges and keep the country together.

Because he was the primary force pushing for the plan's acceptance within the Congress Working Committee, he is considered the leader most "totally in favour" of it in the context of this historical question.