Step 1: Understanding the Concept:
This question is from the story "The Thief's Story" and asks for the age of the narrator, Hari Singh, at the time he met Anil.
Step 2: Detailed Explanation:
The story is narrated by Hari Singh. At the very beginning, he describes his first meeting with Anil. He states, "I was still a thief when I met Anil. And though only 15, I was an experienced and fairly successful hand." This line directly gives his age as 15.
Step 3: Final Answer:
Hari Singh was 15 years old when he met Anil. The correct option is (A).