Where Is the Initial Bond Formation Located in the Covalent

Multiple Choice

Where is the initial bond formation located in the covalent intermediate in the chymotrypsin-catalyzed reaction?

A) between serine and the carbonyl carbon in the peptide backbone
B) between nitrogen and the carbonyl carbon in the peptide backbone
C) between histidine and the carbonyl carbon in the peptide backbone
D) between aspartate and the carbonyl carbon in the peptide backbone