Which best describes the style of this essay?

in middle school all students had to take home-ec, whether we wanted to or not. we thought it was a waste of time, as the oven was so old everything you baked got burnt. the sewing machine kept breaking on us, and our teacher used to forget our names and her lesson plans constantly. she’d walk around calling bernie berbett and jamie jeanette. it didn’t matter how often we corrected her; the next class, she’d do it again. the worst was last year when a group of seventh graders nearly set fire to the school because their oatmeal cookies caught fire in that old, rickety oven!

a) colloquial
b) formal
c) informal
d) all of the above