Select the correct option:
According to cartesian sign convention,
1. The object is always placed on the side of the lens.
1. The object is always placed on the side of the lens.
2. All the distances are measured from the of the lens.
3. The distances measured in the same direction as that of incident light are taken as .
4. The distances measured against the direction of incident light are taken as .
5. The distances measured upward and perpendicular to the principal axis are taken as .
6. The distances measured downward and perpendicular to the principal axis are taken as .