The graph of a function is shown:

A coordinate grid is shown from negative 5 to 5 on both axes at increments of 1. A graph shows three straight lines. The first straight line joins ordered pair negative 3, negative 2 with negative 2, 2. The second straight line joins ordered pair negative 2, 2 with 2, 2. The third straight line joins ordered pair 2, 2 with 4, 0. The ordered pair negative 3, negative 2 is labeled as A, the ordered pair negative 2.5, 0 is labeled as B, the ordered pair negative 2, 2 is labeled as C, the ordered pair 2, 2 is labeled as D, and the ordered pair 4, 0 is labeled as E.

In which interval is the graph constant?

AB
BC
CD
DE