Which Stage of Aerobic Respiration Requires an Input of Two

Question

Which stage of aerobic respiration requires an input of two ATP?  
A) glycolysis
B) acetyl CoA formation
C) citric acid cycle
D) electron transfer phosphorylation
E) fermentation

Accepted Answer

Glycolysis requires an input of two ATP molecules to initiate the breakdown of glucose into two molecules of pyruvate, generating a net gain of ATP as the process continues.