Final answer:
Tsutomu Yamaguchi is the only known person recognized as a survivor of both the Hiroshima and Nagasaki atomic bombings, known as a 'hibakusha.'
Step-by-step explanation:
The only known two-time recognized hibakusha, or survivor of both the Hiroshima and Nagasaki atomic bombings, is A) Tsutomu Yamaguchi. He survived the bombing of Hiroshima on August 6, 1945, and then, having returned to Nagasaki, survived another atomic bomb on August 9, 1945. His unique experiences made him an advocate for nuclear disarmament before his death in 2010. Unlike the other individuals mentioned - Akira Kurosawa, Sadako Sasaki, and Isao Takahata - Tsutomu Yamaguchi has the distinction of being recognized officially by the Japanese government as a survivor of both atomic bombings.