John, a data center specialist, invents a server management tool while working for his data center company in Illinois. There is no employment contract addressing invention rights. The tool is very useful for the company's internal operations and for its customers. John used company servers and his company PC to develop and test the tool. Which of the following are true?

options:

a. Because there was no written employment agreement addressing invention rights, there is now way the company can own the invention.

b. Because the invention was developed using company resources, the company will likely have a shop right, which would allow it to sue other companies for infringing the patent.

c. A shop right is an exclusive license

d. If the company can prove that this invention was developed within the scope of John's employment, the company may own the invention even without a written agreement.