___ flies are easily recognized by their metallic green or blue color.

Bottle or blow flies are known for their metallic green or blue color, which distinguishes them from other flies. TheGeneral Pest Management: Guide for Commercial Applicators - Category 7A(Chapter 7: Flies) describes these flies as common in structures, often attracted to decaying organic matter. Option A (cluster flies) are dull grayish-brown and often found in attics. Option B (house flies) are gray with black stripes, not metallic.