There are several tools to make decisions, but some people might think that the best idea is one that is similar to others used in the past.
So, try to see how to improve any other idea, for example the third one. In which circumstances could be the best idea? What modifications could be done to make it the best one?
Some times people can just use the first idea that has appeared without spending some time to generate more ideas.
Some times people rank the ideas according to some criteria to choose the best ones.
However, in the same way that different techniques, different people, different routines can be used to generates different ideas, also there could be different ways not only to choose the ideas, but to improve them and refine them. Different ideas can have their own strengths and weaknesses. Then choosing an idea become not only a critical thinking process, but a creative one, in which the ideas can be modified and combined till you can feel that is the right one.
Thinking about Wallas four stages of the creative process (preparation, incubation, illumination and verification), we could highlight that having generated a number of ideas, the next step is not only to make a decision about which one is the best, but to try to verify them, looking for modifications and adjustments that can improve the ideas.
Break the rules! Some times the best idea is not the cheapest or the easiest, but the different one, the challenging one!!!
"If at first the idea is not absurd, then there is no hope for it"