Assuming that someone is competent in both C and Rust , IMHO ,  multithreaded/concurrent code that is correct and produces no undefined behavior is better.  Also memory safety is a key feature that Rust brings to the table. In C you are on your own with concurrency and God help you if you are new to C programming. You will get baptism by fire.

 C / C++ and Python are my go-to languages but C tends to be a little messy to code sometimes but gets better with age i guess.