Teacher asks their class of children to come up with a sentence beginning with "I"

After a few children come to the front with predictable statements about having a cat or a certain toy, a child steps up and says
"I is-" and is immediately interrupted by the teacher,
"I am!"
She side-eyes the teacher, frowns and ignores her teacher, starting again
"I is-" again, the teacher interrupts her, this time a little more snappily
"It's I am! Use the proper word!"
The girl turns to look at her this time, eyelids drooped with exasperation.
"Fine," she sighs "I am the ninth letter of the alphabet."