Convert list of data into validation list with all dupes removed

[mountainman88]

Per the table below I have data in a list in column A which can have the same item multiple times, I wish to generate a validation list in column C which only shows each item once (similar to remove duplicates). No VBA please, just using formulas.

Book2
	A	B	C
1	Data		No dupes Validation list
2	dog		dog
3	dog		cat
4	cat		duck
5	cat		camel
6	cat		owl
7	duck
8	camel
9	camel
10	owl
11	owl
12	owl
13	owl
Sheet1

Thanks!

 

[Fluff]

How about

+Fluff 1.xlsm
	A	B	C
1	Data		No dupes Validation list
2	dog		dog
3	dog		cat
4	cat		duck
5	cat		camel
6	cat		owl
7	duck
8	camel
9	camel
10	owl
11	owl
12	owl
13	owl
14
Main

Cell Formulas
Range	Formula
C2:C10	C2	=IFERROR(INDEX($A$2:$A$13,AGGREGATE(15,6,(ROW($A$2:$A$13)-ROW($A$2)+1)/(ISNA(MATCH($A$2:$A$13,C$1:C1,0))),1)),"")