Based on the information present in the given passage, you need to write a correct answer to the given question. A correct answer is one that correctly and completely answers the question. Do not write answers that address the question partially or incorrectly. The correct answer must be contained in the given paragraph.

Example input: Paragraph- Sent 1: Obama was born on August 4, 1961, at Kapiʻolani Maternity & Gynecological Hospital in Honolulu, Hawaii.
Sent 2: He is the only President to have been born in Hawaii.
Sent 3: He was born to a white mother and a black father.
Sent 4: His mother, Ann Dunham (1942-1995), was born in Wichita, Kansas, of mostly English descent, with some German, Irish, Scottish, Swiss, and Welsh ancestry. Question: How old was Obama's mother when he was born?
Example output: 19.
Example explanation: Obama was born in 1961. His mother was born in 1942 and 1961-1942=19. Therefore, any of the following responses are considred correct: '19' and 'almost twenty'.
Q: Paragraph- Sent 1: The city of Edinburgh grew up around the steep, ragged cliff of the Castle Rock and its easily defended summit.
Sent 2: Archaeological excavations have revealed evidence of habitation here as long ago as 900 b.c.
Sent 3: Very little, however, is known about the Rock and its inhabitants in the centuries between its first occupation and the time of the MacAlpin kings.
Sent 4: A few shadowy details have been left to us by the Romans and by an epic poem from the seventh century.
Sent 5: Romans and Britons The Romans invaded Scotland in a.d.
Sent 6: 78–84, where they met a fierce group called the Picts, whom they drove north.
Sent 7: They consolidated their gains by building Antonine's Wall across the waist of Scotland between the Firth of Forth and the River Clyde in about a.d.
Sent 8: Roman legions encountered the strongholds of the Castle Rock and Arthur's Seat, held by a tribe of ancient Britons known as the Votadini.
Sent 9: Little is recorded about this group, but they were probably the ancestors of the Gododdin, whose feats are told in a seventh-century Old Welsh manuscript.
Sent 10: The capital of the Gododdin was Din Eidyn (the "Fort of Eidyn," almost certainly the Castle Rock), whose name lives on in the Edin- of Edinburgh.
Sent 11: Din Eidyn fell to the Angles in 638 and became part of the Anglian kingdom of Northumbria.
Sent 12: It was the first of many times that the Fort of Eidyn would change hands between the kingdoms of the north and the south.
Sent 13: The MacAlpin Kings Four distinct peoples once inhabited the land now known as Scotland: the Picts in the north, the Britons in the southwest, the invading Angles in the southeast, and the Scots in the west.
Sent 14: The Scots were Gaelic-speaking immigrants from the north of Ireland.
Sent 15: Kenneth MacAlpin, who ruled as king of Scots at Dunadd, acquired the Pictish throne in 843, uniting Scotland north of the River Forth into a single kingdom.
Sent 16: He moved his capital — along with the Stone of Destiny (on which Scottish kings were crowned) — to the sacred Pict site of Scone, close to Perth.
Sent 17: His great-great-great-grandson, Malcolm II (1005–1034), defeated the Angles at the Battle of Carham in 1018 and extended Scottish territory as far south as the River Tweed. 
Question: When the Romans invaded Scotland in A.D. 78-84, which group did they drive out?.
A:
The Picts.