What's the difference between a GFI and a GFI C?

As a practitioner in the realm of cryptocurrency and finance, I'm curious to understand the nuances between the terms 'GFI' and 'GFI C'. Could you elaborate on the key differences between these two concepts? Specifically, I'm interested in knowing if they represent different types of financial instruments, have varying risk profiles, or serve distinct purposes within the crypto ecosystem. Additionally, I'd like to know if one is a derivative of the other or if they coexist independently. Clarifying these distinctions would greatly assist me in navigating the complex world of decentralized finance.