The words underneath pictures, diagrams, or graphs are known as what?

Read this excerpt from “the love song of j. alfred prufrock” and answer the question.let us go, through certain half-deserted streets,  the muttering retreats  of restless nights in one-night cheap hotels  and sawdust restaurants with oyster-shells:   streets that follow like a tedious argument  of insidious intentwhat does the use of the word  muttering  suggest? a feeling of discontentthe noise of city streetsthe inability to be understooda sense of lonelinessit's not c so hel0