3.(2² + 1)(2^4 + 1)(2^8 + 1)(2^16 + 1)(2^32 + 1)
= 3.(2² - 1)(2² + 1)(2^4 + 1)(2^8 + 1)(2^16 + 1)(2^32 + 1)
= 3.(2^4 - 1)(2^4 + 1)(2^8 + 1)(2^16 + 1)(2^32 + 1)
= 3.(2^8 - 1)(2^8 + 1)(2^16 + 1)(2^32 + 1)
= 3.(2^16 - 1)(2^16 + 1)(2^32 + 1)
= 3.(2^32 - 1)(2^32 + 1)
= 3.(2^32 - 1)
=> Chọn A