Step 1: Place the subject:
The scene of Lord Buddha begging for alms belongs to the story of his return to Kapilavastu. There, his wife Yashodhara sends their son Rahula to him. It is a famous wall painting of the Ajanta caves.
Step 2: Identify the cave:
This painting is found in Cave No. 17, one of the richest painted caves of Ajanta. Cave 17 also has the Chhaddanta Jataka, the Vessantara Jataka and the Simhala Avadana.
Step 3: Check the other options:
Cave 9 is an early chaitya hall with old paintings. Cave 1 is known for the Bodhisattva Padmapani and Mahajanaka Jataka. Cave 16 is known for the Dying Princess.
Final Answer:
(B) Cave No. 17