The correct answer is option 'C', which is Lion.
Sarnath is a famous archaeological site located near Varanasi in Uttar Pradesh, India. It holds immense historical and religious significance as it is the place where Gautama Buddha, the founder of Buddhism, gave his first sermon after attaining enlightenment. The site of Sarnath is adorned with several ancient structures and sculptures, including the famous Ashoka Pillar.

The Ashoka Pillar at Sarnath is a majestic structure that stands tall and proud, symbolizing the rich history and cultural heritage of the region. It was erected by Emperor Ashoka, the great Mauryan ruler, during the 3rd century BCE. The pillar is made of polished sandstone and features a capital at its top, which is the focal point of the question.

The figure on the top of the pillar at Sarnath is indeed a Lion. This iconic sculpture is known as the Lion Capital of Ashoka and is one of the most well-known symbols of India. It has become the official emblem of the modern Republic of India and is prominently featured on the Indian currency notes.

The Lion Capital of Ashoka is a magnificent piece of artistry and craftsmanship. It consists of four majestic lions standing back to back, symbolizing power, strength, and nobility. The lions are depicted in a seated posture, with their tails curved and touching the ground. The back of each lion is adorned with a circular Dharma Chakra, a Buddhist symbol representing the wheel of law and righteousness.

The Lion Capital of Ashoka also features several other significant elements. Below the lions, there is a cylindrical abacus with beautifully carved figures of four animals: an elephant, a bull, a horse, and another lion. These animals represent the four different directions in Buddhism and symbolize the spread of Buddha's teachings to all corners of the world.

In conclusion, the figure on the top of the pillar at Sarnath is a Lion. The Lion Capital of Ashoka is a remarkable sculpture that holds immense historical, religious, and national importance for India. It represents the power and nobility associated with lions and serves as a symbol of Buddhism and the Indian nation.