Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Date | Opponent# | Rank# | Site | Result | Attendance |
| --- | --- | --- | --- | --- | --- |
| September 12 | #1 Michigan |  | Camp Randall Stadium • Madison, WI | W 21–14 | 68,733 |
| September 19 | #9 UCLA* | #20 | Camp Randall Stadium • Madison, WI | L 13–31 | 71,496 |
| September 26 | Western Michigan* |  | Camp Randall Stadium • Madison, WI | W 21–10 | 67,196 |
| October 3 | Purdue |  | Camp Randall Stadium • Madison, WI | W 20–14 | 68,603 |
| October 10 | #18 Ohio State |  | Camp Randall Stadium • Madison, WI | W 24–21 | 78,973 |
| October 17 | at Michigan State | #14 | Spartan Stadium • East Lansing, MI | L 14–33 | 67,352 |
| October 24 | at Illinois |  | Memorial Stadium • Champaign, IL | L 21–23 | 67,413 |
| October 31 | Northwestern |  | Camp Randall Stadium • Madison, WI | W 52–0 | 70,035 |
| November 7 | at Indiana |  | Memorial Stadium • Bloomington, IN | W 28–7 | 44,218 |
| November 14 | Iowa |  | Camp Randall Stadium • Madison, WI | L 7–17 | 78,731 |
| November 21 | at Minnesota |  | Memorial Stadium • Minneapolis, MN (Paul Bunyan's Axe) | W 26–21 | 47,125 |
| December 13 | vs. Tennessee* |  | Giants Stadium • East Rutherford, NJ (Garden State Bowl) | L 21–28 | 53,220 |
Question:
who was their only opponent in december?
Answer:
Tennessee