Fewer Different TRNA Molecules Exist Than Might Have Been Expected

Multiple Choice

Fewer different tRNA molecules exist than might have been expected for the complexity of its function. This is possible because

A) the third position of the codon does not have to pair conventionally.
B) the second position of the codon does not have to pair conventionally.
C) the anticodon does not have the conventional bases.
D) there are fewer amino acids than there are possible codons.
E) the code is degenerating.