(20 12? In the introductory class, the teacher draws cartoons on the filter paper with phenolphthalein solution, then sprays some liquid X, and the red image immediately appears on the filter paper.

A, dilute hydrochloric acid is acidic, so phenolphthalein can't turn red, so A is wrong;

B, distilled water is neutral, can't make phenolphthalein red, so b is wrong;

C, lime water is alkaline, which can make phenolphthalein turn red, so C is correct;

D, salt solution is neutral, can't make phenolphthalein red, so d is wrong.

So choose C.