Final answer:
Peter the Great did not officially name an heir. His widow, Catherine, succeeded him, whereas his son Alexis predeceased him. Catherine the Great became a ruler later, not as Peter's direct heir.
Step-by-step explanation:
Peter the Great did not officially name an heir before his death. However, historical documents and the succession that followed indicate that Peter's widow, Catherine, effectively became his successor. Peter's son, Alexis, was seen as a potential heir, but he predeceased his father after being convicted of high treason and secretly sentenced to death by Peter. Catherine the Great, on the other hand, came to power some years later as a result of a coup, rather than being directly named as Peter's heir. The option that Peter did not name anyone as his heir is technically accurate because there was no official declaration or undisputed named successor before his death.