A

Step 1: Let's analyze each situation in Column-I and match it with the correct description from Column-II.

(i) Concave mirror, u < f:
When the object distance (u) is less than the focal length (f) in a concave mirror, the image formed is virtual, upright, and diminished. Thus, the correct match is: (i) - [A] Virtual, diminished image.

(ii) Convex mirror, u > f:
A convex mirror always forms virtual images regardless of the object position. The image is diminished and upright. Hence, the correct match is: (ii) - [A] Virtual, diminished image. But since we have already matched [A] with (i), we'll need to re-evaluate our options.

(iii) Concave mirror, f < u < 2f:
In this case, the image formed is real, inverted, and diminished, so this also does not match with [C] as it should be a real image, not virtual.

(iv) Convex mirror, u < f:
Convex mirrors do not have a case for u < f; however, they always produce virtual images that are diminished and upright regardless of the distance. Therefore, (iv) - [A] would not be correct either as they match different conditions.

The only consistent and correct relationships after re-evaluating the initial assumptions are as follows:
(i) - [A], (ii) - [B], (iii) - [C], (iv) - [D].
Thus, the overall matching would be: (i) - [A], (ii) - [B], (iii) - [C], (iv) - [D] corresponds to correct behavior of the mirrors.

Therefore, the correct answer for (i) is: A.