The first reaction in glycolysis that results in the formation of an energy-rich compound (i. e., a compound whose hydrolysis has a highly negative DG°) is catalyzed by:

A) glyceraldehyde 3-phosphate dehydrogenase.
B) hexokinase.
C) phosphofructokinase-1.
D) phosphoglycerate kinase.
E) triose phosphate isomerase.
The answer is A, can someone explain how it’s A?