How will be my Mathematics modules combined?

i took c1 c2 m1 s1 fp1 s2 for AS. I got
c1,2-200 m1-50 s1-80 fp1-70 s2-90. I cashed in mathematics and further mathematics and edexcel combined c1 c2 m1 for maths and s1 s2 fp1 for further.
In A2 i took c34 along with m2 m3 fp2 d1 and also cashed in for both maths and fpmaths. I did REALLY BAD in c34 and m2.
Now how will edexcel combine? if they combine c34 with m2 i might end up with a C for mathematics. OR if they combine c34 with s2 i will get an A. Can they do that to provide the best grade for mathematics?
i am IAL btw.

For maths they could only do the following pairs: M1&M2, M1&S1, M1&D1, D1&S1, S1&S2

So whatever is the best out of those, they would use for maths.

So they will combine c12 c34 with s1 s2, right?

If that's the best one then yeah.