Explanation:

- Red cabbage is known for containing anthocyanins. These pigments are sensitive to pH changes. They appear red or pink in acidic conditions, purple when neutral, and blue or green in alkaline environments.

- Pomegranates are rich in antioxidants, particularly ellagitannins and anthocyanins, but are typically not used as a pH indicator.

- Red leaf lettuce can have anthocyanins but is not widely recognized for use as a pH indicator.

- Radishes also contain anthocyanins but are less notable for dramatic color changes when exposed to different pH levels compared to red cabbage.

Red cabbage is the correct choice for pH-sensitive color changes.