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.