A 3-month-old infant is being worked up for irritability and refusing feedings. Since birth, he has been intermittently fussy and appears lethargic at times. Blood work has been unremarkable. His latest ECG is shown below. It is decided that the child may benefit from an electrophysiological work up with ablative therapy. Where in the myocardium are you going to find the majority of the accessory pathways that are responsible for the findings on the ECG?
A. Right free wall
B. Left free wall
C. Anteroseptal region
D. Posteroseptal region