GKFix MCQ Question

A lens has a power of -4.0 D. What type of lens is it and what is its focal length?

• A. A convex lens with a focal length of +25 cm
• B. A concave lens with a focal length of +25 cm
• C. A convex lens with a focal length of -25 cm
• D. A concave lens with a focal length of -25 cm