The correct answer is option 'D: Bhimbetka'.

Bhimbetka is the largest and most spectacular rock-shelter that bears paintings. It is located in the central Indian state of Madhya Pradesh, specifically in the Vindhya Range of hills. The site is known for its impressive collection of prehistoric rock paintings, which have been recognized as a UNESCO World Heritage Site.

Here is a detailed explanation of why Bhimbetka is considered the largest and most spectacular rock-shelter with paintings:

Historical Significance:
1. Bhimbetka has significant historical and archaeological importance, as it provides insights into the early human settlements and their artistic expressions.
2. The rock shelters at Bhimbetka have been inhabited by humans for over 30,000 years, with evidence of continuous habitation from the Paleolithic period to the medieval era.

Size and Extent:
1. Bhimbetka covers an area of approximately 45 square kilometers, making it one of the largest rock art sites in the world.
2. The site consists of over 750 rock shelters, out of which more than 500 contain rock paintings. These paintings are spread across different rock formations and cliffs.

Artistic Beauty and Diversity:
1. The rock paintings at Bhimbetka showcase an incredible range of artistic styles and themes.
2. The paintings depict various subjects such as humans, animals, hunting scenes, rituals, and daily life activities.
3. The artists used a variety of colors derived from minerals, plant extracts, and animal fats. The pigments have withstood the test of time, retaining their vibrancy even after thousands of years.

Preservation and Conservation:
1. The rock shelters at Bhimbetka have provided a natural protective environment for the paintings, safeguarding them from weathering and erosion.
2. Efforts have been made to preserve and protect the site, including the construction of walkways and viewing platforms to ensure minimal physical damage to the fragile rock art.

Tourism and Visitor Experience:
1. Bhimbetka attracts a large number of tourists and art enthusiasts who visit the site to witness the rich cultural heritage and ancient art forms.
2. The Archaeological Survey of India has developed an interpretive center and a museum at Bhimbetka to enhance the visitor experience and provide insights into the significance of the rock art.

In conclusion, Bhimbetka is considered the largest and most spectacular rock-shelter with paintings due to its vast size, extensive collection of rock shelters, diverse range of artistic styles, historical significance, and efforts towards preservation and conservation. Visiting Bhimbetka offers a unique opportunity to explore the ancient rock art and gain a deeper understanding of human civilization and artistic expressions throughout history.