The correct option is A 507 cm
Given:
Power, P=10 D
We know, P=1f
⇒f=1P=110=0.1 m=10 cm
Maximum angular magnification is achieved, when the image is formed at near point.
So,
v=−D=−25 cm
Using lens formula,
1f=1v−1u
⇒110=1−25−1u
⇒1u=−125−110=−750
∴u=−507 cm
So, the object should be placed at a distance of 507 cm from the magnifier.
Hence, option (A) is the correct answer.