After the Mahaparinirvana of Lord Buddha, the first Buddhist Council was

The correct answer is: A. Rajgriha

The First Buddhist Council was held in Rajgriha (modern-day Rajgir) in the Indian state of Bihar, about 100 years after the death of the Buddha. The council was convened by the Buddha’s disciple Mahakassapa to discuss and codify the Buddha’s teachings. The council was attended by over 500 monks, and it resulted in the creation of the Pali Canon, the oldest collection of Buddhist scriptures.

The other options are incorrect because:

• Option B, Gaya, is the place where the Buddha attained enlightenment.
• Option C, Patliputra, was the capital of the Mauryan Empire.
• Option D, Vaishali, was the site of the Second Buddhist Council.