Which file is used by ld.so to find libraries quickly without actually having to search the directories in its library path?

Which file is used by ld.so to find libraries quickly without actually having to search the directories in its library path?

A.
/etc/ld.so.cache

B.
/var/.cache

C.
/etc/ld.so

D.
/var/ld/cache

E.
/etc/ld.so.conf