3. Six friends A, B, C, D, E and F start climbing a hill together. After some time it is observed that 'D' has reached a position higher than 'B' but not as high as 'E'. 'C' is at a position not higher than 'D' and not lower than 'A', who is not lower than 'F' and not higher than 'B'. Who has climed the highest position?
