How does malu use sarcasm in chapter 10 to deal with selenas insults

In Chapter 10, Malu is in Spanish class. She tends to avoid speaking Spanish and feels it does not come naturally to her, so she is surprised that she tested high enough to be in the advanced class. Selena rudely tells the teacher that Malu cannot speak Spanish, but Malu uses sarcasm tocontradicts that. Later, Selena takes one of Malu's zines. When she gives it back, she says Malu should not leave her “diary lying around” (82). Malu is angry and embarrassed, and wonders why Selena does not like her.