How to use 'etc'?

Question

aaa, bbb, ccc, etc.

aaa, bbb, ccc etc.

aaa, bbb, ccc, etc

aaa, bbb, ccc etc

which is right?

aaa, etc

aaa, etc.

aaa etc

aaa etc.

which is right?

Answer 1

aaa, bbb, ccc, etc. is right

Answer 2

the first one. first of all etc is an abbreviation ( from latin ecetera) so it has to end with a period. and since you're still continuing a list of things by using etc. , there must be a comma after ccc.

Answer 3

Personally I think its aaa, bbb, ccc etc

and

aaa etc