Why Is It Surprising That the Side Chains of Tryptophan

Multiple Choice

Why is it surprising that the side chains of tryptophan residues in lectins can interact with sugars?

A) because the side chain of tryptophan is hydrophilic and sugars are hydrophobic
B) because the side chain of tryptophan is (-) charged and sugars are generally (+) charged or neutral
C) because the side chain of tryptophan can make hydrogen bonds and sugars cannot
D) because the side chain of tryptophan is hydrophobic and sugars are generally hydrophilic
E) None of the answers is correct.