The persistance of C functions

If I use CREATE FUNCTION for a C function in a .so file and then use the
function and then change and recompile the function, what steps are needed
to see the change?

As I see it the options are:
A: do nothing, the function is reloaded on every invocation.
B: Reopen the connection to the backend
C: Restart the postmaster

I suspect B is correct but I would like to hear someone confirm it.