In "homesick," why does ian forbes say, "you'll sing tomorrow…or you'll be sorry"? a. he is angry at jean, and he thinks threatening her will get her to do what he wants. b. ms. williams sent him to convince jean to sing because ian is her best friend. c. he knows that jean will regret it if she does not participate in the songs at school. d. he is afraid of jean's behavior and wants to encourage her to do the singing.