In a solution, methyl orange becomes yellow and phenolphthalein becomes pink. What is the nature of the solution?

Correct answer: Basic

Indicator colours reveal the solution’s acid-base nature. Methyl orange is yellow in a basic or sufficiently less acidic medium, while phenolphthalein is pink in a basic medium, generally above its transition range. Since both observations are consistent with a basic solution, option C is correct. An acidic solution would make methyl orange red and phenolphthalein colourless; a neutral solution would not make phenolphthalein pink.