Final answer:
The easiest way to straighten a skewed horizon in an image is to use photo editing software. This allows correction of the tilt in post-processing, ensuring the photo meets visual expectations and adheres to the rule of thirds for better composition.
Step-by-step explanation:
The easiest way to crop the image to straighten the horizon is A) Use photo editing software to straighten the horizon. When taking photographs, the horizon line should ideally be level to match our visual expectations of a natural landscape or scene. If the horizon is askew, it can distract the viewer and detract from the overall aesthetics of the image.
By placing the adjusted horizon one-third from the top or bottom of the frame, depending on whether you want more land or sky, the composition can become more engaging. A level horizon also applies indoors where floors and ceilings should appear horizontal. Practicing with a camera's rule of thirds grid, if available, can enhance composition skills during shooting, but image adjustment during post-processing remains valuable for correcting any unintended tilts.