This mythological creature was portrayed as a man in Egyptian mythology but as a woman in Greek mythology. Both types of these creatures were intended as guardians of temples, but the most famous creature of this type guarded the temple at Thebes, and posed a riddle to anyone who attempted to enter. This creature had the head of human, the body of a lion, and sometimes, the wings of a bird, and is depicted in a structure in Egypt's Valley of Kings. For 10 points, name this mythological creature, whose riddle Oedipus answered correctly, thus allowing him entrance to Thebes.
a) Sphinx
b) Harpy
c) Minotaur
d) Chimera