Select the option that is related to the fifth number in the same way as the second number is related to the first number and the fourth number is related to the third number. 21 : 529 :: 25 : 729 :: 17 : ?
A, E, I, O, and U are sitting in a row facing north. ‘O’ is sitting next to ‘E’ and ‘U’. ‘A’ is sitting next to ‘I’ who is sitting at the extreme left. ‘U’ is NOT sitting next to ‘A’. Who is in the middle?