What does the doctrine of estoppel prevent?

The correct choice highlights that the doctrine of estoppel prevents a person from asserting a right or claim that could disadvantage or harm another party, especially when that person has previously acted in a way that led the other party to rely on their representations or conduct. Estoppel is rooted in fairness and justice, ensuring that individuals cannot go back on their word or mislead others, especially in legal settings.

In the context of insurance, this principle ensures that if an insurer has led a policyholder to believe something about their policy—such as the coverage limits or conditions—they cannot later argue against that understanding if the policyholder relied on it to their detriment. This serves to maintain trust and integrity in contractual relationships.

Other options like changing policy terms or payment of claims don't directly relate to the fundamental principle of estoppel, which focuses on the protection of parties against unfair surprise or deceit. The relationship between parties and the commitments or representations made is central to the application of estoppel, making it crucial in legal and insurance frameworks alike.