Final answer:
A published magazine interview with Charlie Parker is the best source to learn about his childhood in Kansas City during the 1940s, as it is likely to provide direct insights into his personal experiences.
Step-by-step explanation:
To find the best source about the famous jazz saxophonist Charlie "Yardbird" Parker's childhood in Kansas City during the 1940s, among the given options, a published magazine interview with Charlie Parker would likely provide the most direct and detailed insights into his personal experiences.
Photographs of jazz clubs or a greatest hits album, while valuable for understanding the context and his music, might not contain specific information about his childhood.
The "arts" section of a 1940 Kansas City newspaper could provide contemporary context but might not focus exclusively on Parker's childhood.