What colour does methyl orange give in an acidic solution?

Correct answer: Red

Methyl orange is an acid-base indicator that changes colour over an acidic-to-neutral pH range. In an acidic solution, it appears red; as the solution becomes less acidic and then basic, the colour changes through orange toward yellow. Thus option A is correct. Yellow is associated with the basic-side response, while green and blue are not the characteristic colours used here for an acidic methyl-orange test.