SQL Server syntax - I have this table:

```
C1 - C2 - C3
--------------
 2 - AA - 10
 2 - AA - 20
 3 - AA - 15
 3 - AA - 16
 3 - AA - 56
 1 - BB - 54
 2 - BB - 53
 2 - BB - 89

```

I need a query that will return this result:

```
C1 - C2 - C3
--------------
 3 - AA - 15
 3 - AA - 16
 3 - AA - 56
 2 - BB - 53
 2 - BB - 89

```

So it should return only rows with maximum value of C1 over C2.

How can I do that ?