Living-off others wasps lay their eggs directly into eggs of

Living-off others wasps lay their eggs directly into eggs of various hosts insects in exactly the right way for any suitable size of host egg. If they put too many eggs in a host egg, the developing wasp babies would compete with each other to death for life's necessities. If too few eggs were laid, portions of the host egg would decay, killing babies.

How do they know what happens in those situations? Can you necessarily conclude stuff from ETS outside the lines, I show you next in another one what I mean.

I have a feeling answer XYZ is wrong because
( ) Parisitic wasps learn from experience to determine how many eggs to lay into eggs of different host insects.

they could learn from their mother or others or just know. Is it true the stem just tells you what happens in those situations and you can't infer anything?

XBZ paraphases what the stem is telling you, and hence the right answer.

The size of the smallest host egg that a wasp could theoretically parasitize can be determined by the egg's laying behavior.

It can be determined because of what the egg-wasp has shown? Is my interpretation right?

Thanks
Victor