You will be given a definition of a task first, then some input of the task.
In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).

Context: Constantine IV (c. 652 14 September 685), sometimes incorrectly called "Pogonatos", "the Bearded", out of confusion with his father, was Byzantine Emperor from 668 to 685. His reign saw the first serious check to nearly 50 years of uninterrupted Islamic expansion, while his calling of the Sixth Ecumenical Council saw the end of the monothelitism controversy in the Byzantine Empire., Tiberius III ( Greek : , Tiberios III ; Latin : Tiberius Augustus ; d. 15 February 706 ) was Byzantine emperor from 698 to 21 August 705 . Although his rule was considered generally successful , especially in containing the Arab threat to the east , he was overthrown by the former emperor Justinian II and subsequently executed ., Justinian II (Ioustinianos II) (668 11 December 711), surnamed the Rhinotmetos or Rhinotmetus ("the slit-nosed"), was the last Byzantine Emperor of the , reigning from 685 to 695 and again from 705 to 711. Justinian II was an ambitious and passionate ruler who was keen to restore the Empire to its former glories, but he responded poorly to any opposition to his will and lacked the finesse of his father, Constantine IV. Consequently, he generated enormous opposition to his reign, resulting in his deposition in 695 in a popular uprising, and he only returned to the throne in 705 with the help of a Bulgar and Slav army. His second reign was even more despotic than the first, and it too saw his eventual overthrow in 711, abandoned by his army who turned on him before killing him., Justinian I (482 14 November 565), traditionally known as Justinian the Great and also Saint Justinian the Great in the Eastern Orthodox Church, was a Byzantine (East Roman) emperor from 527 to 565. During his reign, Justinian sought to revive the empire's greatness and reconquer the lost western half of the historical Roman Empire. Justinian's rule constitutes a distinct epoch in the history of the Later Roman empire, and his reign is marked by the ambitious but only partly realized "renovatio imperii", or "restoration of the Empire"., Subject: tiberios iii, Relation: country_of_citizenship, Options: (A) byzantine empire (B) roman empire
Output:
byzantine empire