Select Record With Higher Value
There is at least two ways to do this. One with a derived table, and one with a CTE. These two queries assume there aren't two accounts with the same score. If that's a possibility, we can use another method to get the last ID, or pick a random one. 

;select 
    t.ID
    ,t2.Account
    ,t2.Score
from
    YourTable t
inner join
    (select Account, Score = max(Score)
    from YourTable
    group by Account) t2 on t2.Account = t.Account and t2.Score = t.Score;


;with cte as(
    select RN = row_number() over (partition by Account order by Score desc, id)
            *,
    from YourTable)

select
    ID,
    Account,
    Score
from cte
where RN = 1;