3. Who first suggested the atomic-powered spaceship theory?

Обоснование: В тексте сказано: "In 1945 a new theory about Tunguska was suggested. Aleksander Kazantsev was one of the first Russian scientists to evaluate the atomic bomb explosion at Hiroshima, Japan. He was also intrigued by the mystery of the Tunguska blast and quickly found connections between the two. [...] Kazantsev was the first to suggest that the event was caused by the explosion of an atomic-powered spaceship." Это соответствует варианту (b).

Ответ: b) Aleksander Kazantsev