Final answer:
Phenolphthalein is a chemical that changes color in the presence of hydrogen and/or hydroxide ions. The correct answer is Option A: Phenolphthalein.
Step-by-step explanation:
Phenolphthalein is a chemical that changes color in the presence of hydrogen ions (H+) and hydroxide ions (OH-). It is colorless in acidic solutions and turns pink or red in basic solutions.
Other options like Litmus, Bromothymol blue, and Methyl orange also change color in the presence of acids or bases but are not specific to hydrogen and hydroxide ions. Therefore, The correct answer is Option A: Phenolphthalein.