What Is the Reaction Performed on the Molecule Labeled as Substrate

Multiple Choice

What is the reaction performed on the molecule labeled as substrate in the following diagram? What is the name of the activated carrier?

A) This is a methylation reaction and the activated carrier is ATP.
B) This is a methylation reaction and the activated carrier is S-adenosylmethionine.
C) This is a carboxylation reaction and the activated carrier is ATP.
D) This is a carboxylation reaction and the activated carrier is carboxylated biotin.
E) This is an acetylation reaction and the activated carrier is acetyl CoA.