Explanation:

- Option 1: Estoppel by Silence

This occurs when a person’s silence leads another to believe in a certain state of facts or rights. If someone stays silent when they have a duty to speak up, they may be prevented from later asserting the contrary.

- Option 2: Estoppel by Negligence

This happens when a lack of care or oversight misleads another party. If someone's negligent conduct creates a misunderstanding, they can't later adopt a contrary position.

- Option 3: Estoppel by Election

This type results when a person must choose between two irrevocable alternatives. If they make a choice, they're barred from asserting the other option shortly thereafter.

- Option 4: All the Above

All these situations can indeed lead to estoppel.

Option 4: All the above