Originally Posted by
jphripjah
. . . but I'm curious about your reasoning. Do B-C have 3 oxygen masks? If you stay in C with a lap infant and one member of the demanding couple is in B, do you have access to more oxygen masks than you would have in seat A?
Yes and yes.
Planes are routinely equipped with an extra oxygen mask per row, precisely to allow lap kids one. It can cause problems in larger aircraft when a mum and dad and two lap kids want to be together, but the mask count rules it out.