Final answer:
The strongest example of a blurry photograph is the portrait of her cat with a blurry background. This technique highlights the subject with a sharper focus against a softly blurred background, creating a compelling depth in the photo.
Step-by-step explanation:
An example of a strong blurry photograph would be Option 4: A portrait of her cat with a blurry background. This technique, often referred to as a shallow depth of field, emphasizes the subject by keeping it in sharp focus while the background is blurred. This approach can create a 3D effect on a 2D medium, making the subject stand out and giving the photograph a sense of depth. Moreover, by zooming in on the subject, we reduce distractions from the background and help draw the viewer's eye to focus on the main subject.
Conversely, a photo where the entire image is blurry, such as Option 2, lacks a focal point and thus may not communicate a clear subject or intent, making it a weaker example of a blurry photograph. Similarly, Option 1 and Option 3, where either middle ground or the main subject is blurry, can result in a confusing composition unless the blur is used intentionally for artistic reasons, such as employing atmospheric perspective or conveying movement.