Final answer:
The correct form is 'all need to decide.' This phrase uses the plural verb 'need' because 'all' refers to a group of people, thus requiring a plural verb.
Step-by-step explanation:
The correct phrase to use would be 'all need to decide' because the subject 'all' is a plural indefinite pronoun referring to a group of people. Therefore, the verb should be in the plural form 'need' to match the plural subject.
When groups have to make decisions, it can often lead to diverse opinions and choices. Each member must contribute to reach a conclusion that aligns with the group's goals. In situations where majority opinion is not clear, such as when three families vote on a menu with the understanding that majority wins but end up with a split decision, the process becomes complex. The decision-making process then requires negotiation and compromise among the members.