The green Profit/Loss profile corresponds to a long spot position.
The red profile corresponds to a long futures position (identical capital exposure)
The yellow line corresponds to a long call position. (identical capital exposure)
Let us assume that you own a stock portfolio that exactly reproduces a stock index on which options and futures are traded. The profiles above show that you could have obtained a nearly similar P/L profile with a futures position.
If you had bought calls for the same capital in terms of the underlying index, you could have set a limit to your potential losses, at the expense of a slightly lower profit in case of an increase in the index value.