Answer:
The last image is correct which is attached with this answer.
Explanation:
The rules for three principal rays are:
1. A ray parallel to principal axis, after refraction, passes through the principal focus.
2. A ray that passes through the principal focus, is refracted parallel to the principal axis.
3. A ray that passes through the optical center, goes straight without bending.
All these rule are correctly applied in the last image, which is attached with this answer.
