Which of the following is an important difference between a class I and a class II aminoacyl-tRNA synthetase?

A)The 2 classes proceed through different aminoacyl-AMP intermediates.
B)Class I synthetases first attach the amino acid to the 2'-hydroxyl on ribose,whereas class II attach them to the 3'-hydroxyl.
C)Class I synthetases attach amino acids to the 5'-end of the tRNA,whereas class II attach them to the 3'-end.
D)The 5'-end of the tRNA molecule is phosphorylated only for those tRNAs recognized by class I synthetases.