If you give them ownership of the IP with Option C, then you should ask for a bigger piece of each transaction in your contract, ... keeping in mind they may ch

If you give them ownership of the IP with Option C, then you should ask for a bigger piece of each transaction in your contract, ... keeping in mind they may choose not to renew with the same terms at the end of the contract term (1 year?). If the software is so integral to the success of the project, you might negotiate shared ownership of the IP, so you get something if they sell it.