What is the BEST definition of the phrase a bone of contention?

The decision to sell the property was a bone of contention among the family members.

1. Source of satisfaction

2. Reason for a quarrel

3.small part of the whole

4.stimulating experience

2. Reason for a quarrel

Explanation:

a bone of contention means "a subject or issue over which there is continuing disagreement."

quarrel means "a heated argument or disagreement, typically about a trivial issue and between people who are usually on good term."

they would have to clean it very clean