AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Answer: C — Both myopia and hypermetropia simultaneously
Bifocal lenses contain both concave (upper part) and convex (lower part) lenses. They are prescribed when a person suffers from both myopia and hypermetropia at the same time.
The textbook (Chapter 10, Section 10.2) explicitly states: "Sometimes, a person may suffer from both myopia and hypermetropia. Such people often require bi-focal lenses." The upper concave portion corrects distant vision (myopia) and the lower convex portion corrects near vision (hypermetropia). Cataract is not a refractive error and is not corrected by bifocal lenses.