Explanation

The famous royal portrait panels of the Pallava kings Simhavishnu and Mahendravarman I are found in the Adivaraha Cave at Mamallapuram, also known as the Paramesvara Mahavaraha Vishnugriha. These are two of the earliest identifiable royal portraits in Indian art, each bearing a label inscription naming the king. The Varaha Cave has Varaha and other panels but not these labelled royal portraits. The answer is (C). (Cross-checked with ExamRobot's CDS-I 2024 key and Pallava art-historical sources.)