The Saturn V-C, was just like the Saturn V-B, studied in the same year as the V-C, except it would use a S-IVB second stage to get a payload into a higher orbit.
The Saturn V-C was comparable to the Saturn V-B, which was also examined in the same year. The key difference between the two was that the Saturn V-C utilized a S-IVB second stage to elevate its payload into a more elevated orbit, showcasing distinct design choices.