Is the phrase an idiom?

teachers have eyes behind their heads.

Read the passage from a raisin in the sun. mama: lord have mercy, baby. you done gone and bought your grandmother a hat? travis (very proud): open it! she does and lifts out an elaborate, but very elaborate, wide gardening hat, and all the adults break up at the sight of it. ruth: travis, honey, what is that? travis (who thinks it is beautiful and appropriate): it's a gardening hat! like the ladies always have on in the magazines when they work in their gardens. beneatha (giggling fiercely): travis—we were trying to make mama mrs. miniver—not scarlett o'hara! mama (indignantly): what's the matter with you all! this here is a beautiful hat! (absurdly.) i always wanted me one just like it! which word or phrase from the text best supports the idea that the adults think the hat is inappropriate? “have mercy” (giggling fiercely) (indignantly) “what’s the matter”