What piece of evidence best supports the lesson that Mama was trying to teach Cassie about society?

Mama teaching Cassie to respect people's privacy.

'But, Mama, I wanna know more 'bout him,' I explained. 'I just wanna know how come he's so big.
'You know about as much as you need to know.' she decided. 'And long as Mr. Morrison stays here, that's his house. If he
wants you down there, he'll ask you.