Which of the following commands updates the linker cache of shared libraries?

 The command that updates the linker cache of shared libraries is ldconfig. This command creates, updates, and removes the necessary links and cache for the run-time linker, ld.so, to the most recent shared libraries found in the specified directories. To add a new library directory to the cache, you need to edit the /etc/ld.so.conf file and rerun ldconfig. You can use the -p option to print the current cache contents1.

The other commands are either invalid or unrelated to the linker cache. mkcache, soconfig, and mkldconfig are not standard Linux commands. lddconfig is a typo for ldd, which is a command that prints the shared libraries required by a program2.