Answer:
Frontlighting
Step-by-step explanation:
Option a to c produce different effects and the best in this case is the frontlighting;
Frontlighting refers to as a lighting direction where the broad basic lighting of a photographic subject from the front or the side toward the camera.
The photographic subject here is the wings of a butterfly.
To get the full width of the butterfly's wings, a photographer needs to face the butterfly directly in he front; this is so, because the sides of the butterfly is too tiny and the full details may not be captured.
Also, the sun should be behind the photographer so that light is directed toward the front of the butterfly that the photographer is taking the photo of.