Solution:The Ajanta Caves are a series of ancient Buddhist cave temples in India. Among these caves, Cave No. 19 is indeed the Ajanta Chaityagriha. A "Chaityagriha" is a prayer hall or assembly hall in Buddhism where people would gather for worship and meditation.
Cave No. 09, Cave No. 10, and Cave No. 16 are different caves within the Ajanta complex, but none of them are specifically known as the Ajanta Chaityagriha. Cave No. 16, in particular, is not the Ajanta Chaityagriha.