In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Let me give you an example: Question: When did the operation during which the 704th dropped supplies to allied troops near Nijmegen begin? Passage: The group was occasionally diverted from strategic missions to carry out air support and interdiction missions. It supported Operation Overlord, the invasion of Normandy by attacking transportation targets, including bridges, along with airfields and strong points in France. On D Day, the squadron and the rest of the 446th Group led the first heavy bomber mission of the day. The 446th aided ground forces at Caen and Saint-Loduring July by hitting bridges, gun batteries, and enemy troops. During Operation Market Garden, the attempt to seize a bridgehead across the Rhine in the Netherlands, the 704th dropped supplies to allied troops near Nijmegen. It struck lines of communications during the Battle of the Bulge. During Operation Varsity in March 1945, it supplied ground and airborne troops near Wesel. The squadron flew its last combat mission on 25 April 1945 against Salzburg, Austria. The group had flown 273 missions and had lost 58 aircraft during the war,
. Links: a. Allies of World War II b. Wesel c. Operation Market Garden d. Air Support.
The answer to this example can be: c
Here is why: The passage describes the 704th's actions during Operation Market Garden.

OK. solve this:
Question: How many teams total are there in the National Football League? Passage:The Pittsburgh Steelers compete in the National Football League (NFL) as a member club of the American Football Conference (AFC) North division. Founded in 1933, the Steelers are the oldest franchise in the AFC; seven franchises in the National Football Conference (NFC) have longer tenures in the NFL. The team struggled to be competitive in its early history, posting winning records in just 8 of its first 39 seasons. Since the AFLNFL merger in 1970, however, it has appeared in eight Super Bowls and one of only two teams, along with the New England Patriots have won the Super Bowl six times. The six championships place the Steelers fourth in the league in terms of total championships (including those prior to the first Super Bowl), trailing only the Green Bay Packers (13 championships), the Chicago Bears (9) and the New York Giants (8). The club's 15 AFC Championship Game appearances are second all-time, behind the Patriots (16). In addition, they have hosted the second-most conference championship games (11) than any franchise in either conference, and are tied for second with the Dallas Cowboys and Denver Broncos with eight Super Bowl appearances; the Patriots currently hold the record of eleven appearances, as of 2019.
Links: a. National Football League b. American Football Conference c. National Football Conference d. AFC Championship Game
Answer:
a