Options are 6: A, B, C, D, E, F.

1) The voter marks with 1 the most preferred option. Then he can rank downwards as far as he is concerned.

Example:
A) 1 1 1
B) 2 2
C) 3 3
D) 4
E) 5
F) 6

2) The voter can mark the option he wants least and then as far up as he wishes.

Example:
A)
B)
C)
D) 4
E) 5
F) 6 6

3) The voter can mark both from above and below.

Example:
A) 1
B) 2
C)
D)
E) 5
F) 6

4) The voter can give to more than one option the same rank.

Example:
A) 1 1 1 1
B) 1 1 2 1
C) 2 2
D)
E) 6
F) 6 6