A credit analyst has been tasked with adding more green bonds to his firm's portfolio without sacrificing yield, or spread value. He created this Fixed Income Worksheet on the Terminal function FIW that shows U$.$S$.$ Electric bonds with a BBB$+$ to BBB$-$ rating.Then he used the Group By field to sort the data into green bonds $($the green bubbles$)$ and non$-$green bonds $($blue bubbles$).$ He also added a regression curve for the displayed bonds: the ones above the curve have a higher yield and the ones below it have a lower yield. In which pink lettered section is the analyst most likely to start his deeper credit research?