Q: You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
It was 7. See source.

"Mantle announced his retirement on March 1, 1969, and in 1974, as soon as he was eligible, he was inducted into the Baseball Hall of Fame; his uniform number 7 was retired by the Yankees."
A:
What was Mickey Mantle's playing number?