The image of a small electric bulb fixed on the wall of a room is to be obtained on the opposite wall $3\;m$ away by means of a large convex lens. What is the maximum possible focal length (in $m$) of the lens required for the purpose?

  • A
    $1.25$
  • B
    $0.25$
  • C
    $0.50$
  • D
    $0.75$

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