sql

I have 3 tables.

table_a
marca
15145
1455
1333

table_b
data
11-01-2002
11-02-2002

table_c
marca data
15145 11-01-2002
15145 11-02-2002
1455 11-01-2002
1333 11-01-2002
1333 11-02-2002

After interogation of the tables I need this kind of result:

marca data
1455 11-02-2002

(I want to receive the records which are a combitation of fields of table_a and table_b and that are not in the table_c)

How can I do that?

Thanks!