Oracle 11g Release 2

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

with foo(id, ColA, ColB, ColC, State, ValidFrom, LastUpdate) as (
    select 1, 1, 1, 1, 10, null,              date '2018-10-10' from dual union all -- Excluded
    select 2, 1, 1, 1, 70, null,              date '2018-10-09' from dual union all -- lower State
    select 3, 1, 1, 1, 90, null,              date '2018-05-05' from dual union all -- older LastUpdate
    select 4, 1, 1, 1, 90, null,              date '2018-07-12' from dual union all -- Should Win
    select 5, 1, 2, 1, 90, date '2018-10-18', date '2018-07-12' from dual union all -- Should Win
    select 6, 1, 2, 1, 90, null,              date '2018-11-18' from dual union all -- loose against ValidFrom
    select 7, 3, 2, 1, 90, date '2018-12-02', date '2018-08-04' from dual union all -- lower ValidFrom
    select 8, 3, 2, 1, 70, date '2018-10-19', date '2018-11-17' from dual union all -- lower state
    select 9, 3, 2, 1, 90, date '2018-10-18', date '2018-08-14' from dual ) -- Should win
select * 
  from (
    select row_number() over (
                        partition by cola, colb, colc 
                        order by state desc, validfrom desc nulls last, lastupdate desc) rn, 
           foo.*
      from foo)
  where rn = 1

RN	ID	COLA	COLB	COLC	STATE	VALIDFROM	LASTUPDATE
1	4	1	1	1	90	null	12-JUL-18
1	5	1	2	1	90	18-OCT-18	12-JUL-18
1	7	3	2	1	90	02-DEC-18	04-AUG-18