The wrong rule of sign convention is :
(i) All distances are measured from the centre of curvature of the mirror taken as origin.
(ii) The distances measured along the principal axis in the direction of incident light are positive.
(iii) The distances above the principal axis are taken positive.
(a) (i)
(b) (ii)
(c) (iii)
(d) both (i) and (ii)

(a) (i)

Reason — The rules of sign convention are :

(i) All distances are measured from the pole of the mirror taken as origin.

(ii) The distances measured along the principal axis in the direction of incident light are positive while those opposite to the incident light are negative.

(iii) The distances above the principal axis are taken positive and those below the principal axis are taken negative.