A

Step 1: To solve this question, we need to understand the image formation characteristics of concave and convex mirrors based on different types of objects (real and virtual).

Image Formation by Concave Mirror:
1. **Real Object:**
- When a real object is placed beyond the center of curvature, the concave mirror forms a real and inverted image. If the object is placed at the center, the image size is the same.
- If the object is placed between the center of curvature and the focus, the image is real, inverted, and larger than the object.
- If the object is placed at the focus, the image is at infinity; and if between the focus and the mirror, the image is virtual and enlarged.

2. **Virtual Object:**
- A virtual object can lead to a real image of smaller size when the virtual object is between the focus and the mirror.

Image Formation by Convex Mirror:
- Convex mirrors always form virtual images that are smaller than the object, regardless of the object's position.

Now, we match each statement:
(i) Image of the same size as the object is possible - Correct: [A] for concave mirror in case of real object (i.e., placed at the center of curvature)
(ii) Virtual image of a size greater than that of the object is possible - Incorrect: Convex mirrors do not form enlarged images.
(iii) Real image of a size smaller than that object is possible - Correct: [C] for concave mirror in case of virtual object (implying it can produce smaller real images when virtual objects created due to reflections are considered).
(iv) Real and erect image is possible - Incorrect: Convex mirrors produce only virtual images.

Final Matching:
- (i) → [A]
- (ii) → [not applicable]
- (iii) → [C]
- (iv) → [not applicable]

Therefore the only correct match for (i) is option A, as stated in the question.
Hence, the answer is option A.