Is the most efficient

Which are correct:
1-Honesty is best.
2-Honesty is the best.

3-Honesty is most efficient.
4-Honesty is the most efficient.

Is there a difference in the meanings of "1" and "2", and of "3" and "4"?

I guess the context would define what is being compared. The intended meaning might be "Honesty is the best line of defense." or "the best strategy" or.... "the best virtue".

I know that "3" could mean "Honesty is very efficient," But could it have a meaning in a context where honesty is being compared with other things?

Gratefully,
Navi.