What causes Alfonso and Ernie to argue in “Broken Chain"?

A. the idea that Ernie should get to eat more frijoles because he is older than Alfonso

B. the fact that Alfonso laughs at Ernie when he tells him about the girls who stood him up

C. the fact that although Alfonso is younger, he has a girlfriend before Ernie does

D. the idea that Alfonso's new girlfriend might be the same girl who stood Ernie up