Table:
0
A
B
C
D
E
1
Class
Number range
Quantity
Year(s) Built
Type
2
P 1 ( de )
1501 –1550
56
1885–1891
1′B n2
3
P 2
1551–1600
166
1877–1884
1B n2
4
P 2
1551–1600
76
1878–1883
1B n2
5
P 2
1551–1600
5
1886
2′B n2
6
P 3 ( de )
1601–1700
3
1891
2′B n2v
7
P 3 1 ( de )
1601–1700
685
1885–1899
1B n2
8
P 3 2 ( de )
1701–1800
131
1887–1903
1B n2v
9
P 4 1 ( de )
1801–1900
2
1891
2′B n2
10
P 4 1 ( de )
1801–1900
55
1891–1892
2′B n2
11
P 4 1 ( de )
1801–1900
424
1893–1901
2′B n2
12
P 4 1 ( de )
1801–1900
1
1898
2′B h2
13
P 4 2 ( de )
1901–2000
2
1891
2′B n2v
14
P 4 2 ( de )
1901–2000
707
1898–1910
2′B n2v
15
P 4 2 ( de )
1901–2000
(5)
(1907)
2′B n2v
16
P 6
2101–2300
272
1901–1910
1′C h2
17
P 7 ( de )
2301–2400
18
1899–1902
2′C n4v
18
P 8
2401–2800
3498
1906–1923
2′C h2
19
( P 10 )
(from 2801)
260
1922–1925
1′D1′ h3

Questions and formulas:
Question: What is the number range for the 56 quantity?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,C1=56),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E19,C2:C19=56),2))
Level: medium