What colour does methyl orange give in an acidic solution?

Correct answer: Red

Methyl orange is an acid-base indicator with a characteristic colour transition. In an acidic solution, its observed colour is red; as the medium becomes less acidic and then basic, the colour changes through orange toward yellow. Therefore option A is correct. Yellow corresponds to the basic-side response of methyl orange, while green and blue are not its standard acidic colour in this test.