Which theme statement is most supported by Robert Frost’s "The Road Not Taken”?

It is best to exercise great caution when making decisions, because there is no way to go back and redo the past.
The only way to be content with decisions we have made is to stop thinking about the past and focus on the future.
Because it is human nature to want to be like others, it is best to make a decision based on others’ opinions.
Even if we are happy with the decisions we have made, it is human nature to wonder “what might have been.”