Table:
0
A
B
C
D
E
F
1
Outcome
Year
Championship
Surface
Opponent in the final
Score in the final
2
Winner
1998
Canada (Toronto)
Hard
Richard Krajicek
7–6 (7–3) , 6–4
3
Winner
1998
Cincinnati
Hard
Pete Sampras
1–6, 7–6 (7–2) , 6–4
4
Runner-up
1999
Rome
Clay
Gustavo Kuerten
4–6, 5–7, 6–7 (6–8)
5
Runner-up
1999
Cincinnati
Hard
Pete Sampras
6–7 (7–9) , 3–6
6
Runner-up
2001
Canada (Montreal)
Hard
Andrei Pavel
6–7 (3–7) , 6–2, 3–6

Questions and formulas:
Question: What is the surface for the year 2001?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,B1=2001),4))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F6,B2:B6=2001),4))
Level: medium