Table:
0
A
B
C
D
E
1
Ship
Builder
Laid down
Launched
Commissioned
2
Dolfijn
Rotterdamse Droogdok Mij
30 December 1954
20 May 1959
16 December 1960
3
Zeehond
Rotterdamse Droogdok Mij
30 December 1954
20 February 1960
16 March 1961
4
Potvis-class
Potvis-class
Potvis-class
Potvis-class
Potvis-class
5
Potvis
Wilton-Fijenoord, Schiedam
17 September 1962
12 January 1965
2 November 1965
6
Tonijn
Wilton-Fijenoord, Schiedam
26 October 1962
14 June 1965 1965
24 February 1966

Questions and formulas:
Question: The Zeehond was built by whom?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1="zeehond"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E6,A2:A6="zeehond"),2))
Level: medium