Question: John of Arsuf was the regent of Jerusalem under which memberof the Hohenstaufen dynasty?

Context paragraphs:
Balian of Arsuf: Balian of Ibelin (1239 – 29 September 1277) was the Lord of Arsuf from 1258 until the early 1260s (probably 1261), when he leased/rented it to the Knights Hospitaller.  He was the son and successor of John of Arsuf, Constable of Jerusalem.  At the time when he leased/rented it to the Hospital, his fief of Arsuf was worth six knights' fees and twenty sergeants'; the Hospital took up his obligations with the exception of the "servise de cors".

William Malconvenant: William Malconvenant also known as William Malcovenant (French: "Guillaume Malconvenant" , Latin: "Guillelmus Malconvenant" , Arabic: Ghuliyalm Malqumanant:‎ ‎ , Italian: "Guglielmo Malconvenant") (floruit 1183–1203), was an Italo-Norman baron in Sicily.  He was an "amiratus" (admiral) of the Kingdom of Sicily in the late 12th and early 13th centuries, during the reign of the Hohenstaufen dynasty.

Beatrice II, Countess of Burgundy: Beatrice II (1193 – 7 May 1231) reigned Countess Palatine of Burgundy from 1205 until her death.  She was a member of the Swabian Hohenstaufen dynasty, the daughter of Count Otto I of Burgundy and Margaret of Blois, thereby a granddaughter of Emperor Frederick Barbarossa.

Judith of Hohenstaufen: Judith of Hohenstaufen, also known as "Judith of Hohenstaufen" or "Judith of Swabia" (  1133/1134 – 7 July 1191), a member of the Hohenstaufen dynasty, was Landgravine of Thuringia from 1150 until 1172 by her marriage with the Ludovingian landgrave Louis II.  She was baptized as "Judith", but was commonly called "Jutta" or "Guta".  Sometimes the Latinate form "Clementia" was used, or "Claritia" or "Claricia".

Muslim settlement of Lucera: The Muslim settlement of Lucera was the result of the decision of Holy Roman Emperor Frederick II of the Hohenstaufen dynasty (1194–1250) to move 20,000 Sicilian Muslims to Lucera, a settlement in Apulia in southern Italy.  The settlement thrived for about 75 years.  In 1300, it was sacked by the Christian forces of Charles II of Naples and its Muslim inhabitants were exiled or sold into slavery.

Maria of Swabia: Maria of Hohenstaufen (3 April 1201 – 29 March 1235) was a member of the powerful Hohenstaufen dynasty of German kings which lasted from 1138 to 1254.  She is also known to history as Marie of Swabia.

War of the Lombards: The War of the Lombards (1228–1243) was a civil war in the Kingdom of Jerusalem and the Kingdom of Cyprus between the "Lombards" (also called the imperialists), the representatives of the Emperor Frederick II, largely from Lombardy, and the native aristocracy, led first by the Ibelins and then by the Montforts.  The war was provoked by Frederick's attempt to control the regency for his young son, Conrad II of Jerusalem.  Frederick and Conrad represented the Hohenstaufen dynasty.

John of Arsuf: John of Ibelin (c. 1211–1258) was the Lord of Arsuf (or Arsur) from 1236 and Constable of Jerusalem from 1251.  He was a younger son of John I of Beirut.  His elder brother, Balian, inherited Beirut.  He served as regent of Jerusalem on two occasions: 1253–1254 for Conrad II and 1256–1258 for Conrad III.  He was lieutenant for the regent on three occasions: 1247–1248 and 1249–1252 for Henry I of Cyprus and 1258 for Plaisance of Antioch.

Conrad IV of Germany: Conrad (25 April 1228 – 21 May 1254), a member of the Hohenstaufen dynasty, was the only son of Emperor Frederick II from his second marriage with Queen Isabella II of Jerusalem.  He inherited the title of a King of Jerusalem (as Conrad II) upon the death of his mother in childbed.  Appointed Duke of Swabia in 1235, his father had him elected King of Germany (King of the Romans) and crowned King of Italy (as Conrad IV) in 1237.  After the emperor was deposed and died in 1250, he ruled as King of Sicily (Conrad I) until his death.

La Magione, Palermo: The Basilica of the Most Holy Trinity (Italian: Basilica della Santissima Trinità), commonly known as Basilica del Cancelliere, Basilica La Magione or simply La Magione, is a Norman church of Palermo.  It was completed in 1191 and is the last church built in the capital of the Norman Kingdom of Sicily during the period of the Hauteville dynasty.  Its foundation is linked to the Chancellor of the Kingdom, Matthew of Ajello.  Initially attributed to the Cistercians, during the period of the Hohenstaufen dynasty the church became the house of the Teutonic Order.  It is located in the quarter of the Kalsa, within the historic centre of Palermo.

Supporting paragraphs: John of Arsuf Conrad IV of Germany
Answer: Conrad