$A$ student prepared solutions of $(i)$ an acid and $(ii)$ a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless,how will she distinguish between the two?

• A
  By tasting the solutions.
• B
  By using a chemical indicator like phenolphthalein or natural indicators like turmeric or china rose.
• C
  By checking the smell of the solutions.
• D
  By observing the colour of the solutions.