He can conquer the world who can conquer himself.

The above sentence is said to be a motto and appeared in one of the Chinese English tests as follows:

The great man believes in the motto _____ he can conquer the world ____ can conquer himself.

a--that ..... who
b--that ...... where
c--which ...... in which
d-- and....and

The given answer is 'a'.
My question is: is there really such a motto with a grammatical structure like this? A google search has not produced a motto line close to that. It looks and sounds very strange to me.

Thank you.