Choose the letters whose water images are identical to the letter itself.

(A) D

(B) N

(C) Z

(D) C

Choose the correct answer from the options given below:

A water image is the reflection of an object across a horizontal axis, as if viewing it reflected in still water.

For a letter's water image to be identical to itself, the letter must have horizontal line symmetry (symmetric about a horizontal axis passing through its center).

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Examining letter D:

D has a vertical line on the left and a curved portion on the right. When reflected across a horizontal axis through its center, the top curve becomes the bottom curve and vice versa, but the overall shape remains identical to D.

D has horizontal line symmetry. ✓

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Examining letter N:

N consists of two vertical lines connected by a diagonal line from bottom-left to top-right. When reflected across a horizontal axis, the diagonal would run from top-left to bottom-right, creating a reversed N shape.

N does not have horizontal line symmetry. ✗

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Examining letter Z:

Z has a horizontal line at the top, a diagonal line, and a horizontal line at the bottom. When reflected across a horizontal axis, the top and bottom switch positions, and the diagonal reverses direction, resulting in a different orientation.

Z does not have horizontal line symmetry. ✗

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Examining letter C:

C is an arc opening to the right. When reflected across a horizontal axis through its center, the top arc becomes the bottom arc and vice versa, but the overall shape remains identical to C.

C has horizontal line symmetry. ✓

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Only letters D and C have water images identical to themselves.

Therefore, the correct answer is Option 3: (A) and (D) only.