Could you help me build an option value formula from the binomial option pricing model(with discrete probability factors). The problem is that I am trying to find out the value function of R&D project where individual development research(performance, reliability, yield, etc) must be all accomplished. I made the sample Binomial tree below to explain the problem situation. I divided research into 2 types: 'performance research' and 'other research' in order to make the situation simpler. I think option price can be solved by backwarding. You can modify the binomial tree or the problem if needed.

Idea: when developing new products, R&D process should be done before manufacturing. Often R&D projects are consist of multiple development research. So, my goal is to make the value formula of R&D project( or value or contribution rate formula of individual research if possible) using real option method.