"For instance" indicates that an example is about to come. My older brother is the funniest person I know. For instance,

A
he’s often crying and unhappy.

B
he recently became afraid of his own shadow.

C
he can make our mother laugh just by rolling his eyes.

D
I often feel myself longing for sleep when he speaks.

a source card is mage during research to tell the facts about the source one is using.

since it is asking for her reaction to elnora's trouble at school you can rule out any answers with a positive response (b). then you can rule out (d), this is because it does not show the mother's reaction but the daughter's response. that leaves you with two options (a) and (c), by looking at the options you can rule out (c) because it isn't referring back to elnora's issues at school.