Achemical indicator that changes colors depending on the concentration of h+ in the solution is called a

Answer is: acid-base indicator or pH indicators.

Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations.
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄). Phenolphthalein is colorless in acidic solutions and pink in basic solutions.
Another example is methyl orange. It is red colour in acidic solutions and yellow colour in basic solutions.

Ibelieve the answer is d