What is maximum magnification that can be obtained from a convex lens of focal length 5 cm. (the least distance vision is 25 cm)

$(a)\;10 \\ (b)\;8 \\ (c)\;6 \\ (d)\;20$

For a convex lens
maximum magnification
$m_{max}=1+ \large\frac{d}{f}$
$\qquad= 1+\large\frac{25}{5}$
$\qquad=6$
Hence c is the correct answer.