Final answer:
The woman in the Theban cycle who is carried out to sea on the back of a bull is Europa, who was abducted by Zeus in the guise of a bull to Crete where she became queen.
Step-by-step explanation:
The woman being carried out to sea on the back of a bull as part of the Theban cycle is Europa. This mythological account is one aspect of Greek mythology that describes how Zeus, disguised as a bull, abducted Europa from her homeland and took her across the sea to Crete.
There, she became the queen and mother of King Minos, one of the principal figures in the Theban cycle. The story of Europa and Zeus is pivotal in Greek mythology and has been depicted in various forms of art, including vase paintings and sculptures.