It says on google
<span>An acid-base indicator (e.g., phenolphthalein) changes color depending on the pH. Redox indicators are also frequently used. A drop of indicator solution is added to the titration at the start; when the color changes the endpoint has been reached, this is an approximation of the equivalence point.</span>
Don’t press the link above me. It causes viruses
The answer would be letter C - solution.
A mixture should be homogeneous for a light not to be scattered. This is because particles are distributed evenly throughout the mixture which allows light to pass directly. In your choices, the solution allows a beam of light to pass through a liquid in a test tube without scattering.
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