Table:
0
A
B
C
D
E
1
endowment id
school id
donator name
amount
2
1
1
Monte Plata
9.51
3
2
2
San José de Ocoa
9.83
4
3
3
Distrito Nacional
9.55
5
4
3
Valverde
9.73
6
5
3
San Cristóbal
9.05
7
6
4
Santo Domingo Este
8.99
8
7
4
Santiago
8.85
9
8
5
Duarte
8.53
10
9
6
Com. Dom. En Estados Unidos
8.43
11
10
7
La Vega
8.82
12
11
8
Peravia
8.33

Questions and formulas:
Question: Show all donor names.
Formula: UNIQUE(C1)
Formula2: UNIQUE(C2:C12)
Level: easy
Question: Donators' names 
Formula: UNIQUE(C1)
Formula2: UNIQUE(C2:C12)
Level: easy
Question: What are the names of donators?
Formula: UNIQUE(C1)
Formula2: UNIQUE(C2:C12)
Level: easy