The setting, The main character, The theme, The problem and solution. The begining, middle or end. And lastly the POV (point of view)
The friendly-looking puppy pawed on the window to attract the attention of the people walking by on the sidewalk.
The rest didn't make sense and what is the - c?
I would say A
this is because it is formed more properly, it gives the best reason out of the options, and includes a thorough fact.
hope this helps
3D printing is incredibly resource efficient since the only material consumed is what passes under the laser (or through the extruder, etc.), whereas traditional manufacturing requires the use of extra materials (molds for injection molding, scraps for perforated sheet metal assembly, etc.)