My poor , poor 1st years . Mitsu was n't very energetic today , so he was n't running around , but lots of other boys were . I do n't know what got into them .
Why was Mitsu and the first years so tired ?
Pick the best answer from the following options:
A. None of the above choices .
B. They are being deprived of sleep .
C. They are hurting from fighting .
D. They are not used to school .


D