D, h, and p are coplanar ?

Answer:
Yes
Step-by-step explanation:
But if you stuck a pencil through the center of the picture the line that it makes would not be coplanar.
Answer:
Yes
Step-by-step explanation:
Co-planer means they exist on the same plane.
HDP is co-planer.
GDP is co-planer.
HPG is co-planer.
HDG is collinear. This is because they exist on the same line.