Table:
0
A
B
C
D
E
1
feature id
feature type code
feature name
feature description
other available features
2
2
Amenity
AirCon
Air Conditioning.
3
3
Amenity
Pool
Swimming Pool.
4
4
Security
BurglarAlarm
Burglar Alarm

Questions and formulas:
Question: How many available features are there in total?
Formula: ROWS(UNIQUE(E1))
Formula2: ROWS(UNIQUE(E2:E4))
Level: easy