Question: Which one, Boğaziçi University or Basilica Cistern, was built in the 6th century during the reign of Byzantine Emperor Justinian I?

Context paragraphs:
Institutes of Justinian: The Institutes of Justinian (Latin: "Institutiones Justiniani" or "Justinian's Institutes") is a unit of the "Corpus Juris Civilis", the sixth century codification of Roman law ordered by the Byzantine emperor Justinian I.  It is largely based upon the Institutes of Gaius, a Roman jurist of the second century A.D.  The other units in the "Corpus Juris Civilis" are: the "Digest", the "Codex Justinianus", and the "Novellae Constitutiones" ("New Constitutions" or "Novels").

Papatzys: Papatzys (died 704) was, in the account of Theophanes the Confessor, the Khazar "tudun" of Kerch during the sojourn of Byzantine emperor Justinian II in Phanagoria.  He was dispatched, along with Balgitzin, by Busir Khagan to kill Justinian in 704, after Busir was bribed by Tiberius III.  Justinian's Khazar wife Theodora warned him in advance and Justinian escaped by sea, but not before murdering both Papatzys and Balgitzin.

Battle of Tricamarum: The Battle of Tricamarum took place on December 15, 533 between the armies of the Byzantine Empire, under Belisarius, and the Vandal Kingdom, commanded by King Gelimer, and his brother Tzazon.  It followed the Byzantine victory at the Battle of Ad Decimum, and eliminated the power of the Vandals for good, completing the "Reconquest" of North Africa under the Byzantine Emperor Justinian I.  The main contemporary source for the battle is Procopius, "De Bello Vandalico", which occupies Books III and IV of his magisterial "Wars of Justinian".

Anastasius (jurist): Anastasius was a Graeco-Roman jurist, ostensibly from the city of Dara, living in the 5th or 6th century CE.  He was written of as an interpreter of the Roman compendium of laws known as the "Digest".  He is cited in the later "Basilika", in which, on one occasion, his opinion is placed in opposition to that of Stephanus of Byzantium.  Aside from this, there is little evidence in his surviving fragments to guess at the century in which he lived or suppose him to have been a contemporary of the Byzantine Emperor Justinian I (r. 527–565).  Classical scholar Reitz, however, considered it certain that he was so, and accordingly marked his name with an asterisk in the list of jurists appended to his edition of Theophilus.  The name "Anastasius" is so common that it is difficult to identify him with others possessing the name, but it may be stated that among more than forty persons mentioned with the name, the scholar Johann Albert Fabricius mentions one who was Roman consul in 517 CE.  Procopius relates that Anastasius, who had quelled an attempt to usurp imperial power in Anastasius's native city of Dara, and had acquired a high reputation for intelligence, was sent on an embassy to the Persian shah Khosrau I in 540 CE.  This Anastasius was at first detained against his will by Khosrau, but was sent back to Justinian, after Khosrau had destroyed the city of Sura.

Column of Justinian: The Column of Justinian was a Roman triumphal column erected in Constantinople by the Byzantine emperor Justinian I in honour of his victories in 543.  It stood in the western side of the great square of the Augustaeum, between the Hagia Sophia and the Great Palace, and survived until the early 16th century, when it was demolished by the Ottomans.

Narses: Narses (also sometimes written Nerses; Armenian: Նարսես ; Greek: Ναρσής ; 478–573) was, with Belisarius, one of the great generals in the service of the Byzantine Emperor Justinian I during the Roman reconquest that took place during Justinian's reign.  A Romanized Armenian, Narses spent most of his life as an important eunuch in the palace of the emperors in Constantinople.

Basilica Cistern: The Basilica Cistern (Turkish: "Yerebatan Sarnıcı – "Cistern Sinking Into Ground"" ), is the largest of several hundred ancient cisterns that lie beneath the city of Istanbul (formerly Constantinople), Turkey.  The cistern, located 500 ft southwest of the Hagia Sophia on the historical peninsula of Sarayburnu, was built in the 6th century during the reign of Byzantine Emperor Justinian I.

Sarosius: Sarosius (Greek: Σαρώσιος "Sarṓsios" ), also called Sarodius (Σαρώδιος "Sarṓdios") or Saroes (Σαρόης "Saróēs"), was the king of the Alans in the early 6th century while they were still in Ukraine.  He acted as diplomatic negotiator between the Central Asian Pseudo-Avar refugees led by Kandik and the Byzantine emperor Justinian I in 557 and then again between Justin II and the Turks in 569.  From the latter we learn that the Avars whom Sarosios helped in 557 were in fact renegades from the Hephthalites (who surrendered to the Göktürks and Sassanid Persia in 567) and apparently had no right to use the title of Avar Khagan.  The diplomatic ties that Sarosios fostered led to the Göktürks' agreement with Emperor Maurice in 598, to support a ruler, Sandilch, approved of by the Ashina clan.

Boğaziçi University: Boğaziçi University (also known as Bosphorus University, Turkish: "Boğaziçi Üniversitesi" , "Boğaziçi" literally meaning Bosphorus in Turkish) is a major research university located on the European side of the Bosphorus strait in Istanbul, Turkey.  It has four faculties and two schools offering undergraduate degrees, and six institutes offering graduate degrees.  The language of instruction is English.

Germanus (cousin of Justinian I): Germanus (Greek: Γερμανός ; died 550) was an East Roman (Byzantine) general, one of the leading commanders of Emperor Justinian I (r. 527–565).  Germanus was Emperor Justinian's cousin, and a member of the ruling dynasty.  He held commands in Thrace, North Africa, and the East against Persia, and was slated to command the final Byzantine expedition against the Ostrogoths.  Having married into the Gothic Amal royal line through his second wife Matasuntha and a distinguished service record, at the time of his sudden death, he was considered the probable heir to Emperor Justinian.

Supporting paragraphs: Boğaziçi University Basilica Cistern
Answer: The Basilica Cistern