After Cadmus left the Oracle of Delphi, he followed the cow, and where the cow stopped, he began to build Thebes. Before he could begin, he faced a challenge. What challenge did Cadmus face?
A.
He had to find his sister Europa.
B.
He had to go to the Oracle of Delphi.
C.
He had to fight and defeat a dragon.
D.
He had to witness the deaths of his daughters.