Verbal Reasoning — Classification (Always/essential component): A camera must always include which part? Focus on the fundamental optical component required for image formation, not accessories. Choose the item that every camera necessarily has.

Concept/Approach
All cameras form images by focusing light; this requires an optical system — a lens (or lens assembly/pinhole equivalent). Among the given choices, lens is the essential standard component.

Option Analysis

• Reels — only for analog film cameras; not for digital.
• Flash — optional.
• Stand — optional accessory (tripod).
• Lens — fundamental for focusing light. Correct.

Final Answer
Lens.