Function - allocate new string and copy X characters

I'm supposed to write a function that receives a string and a number X as arguments, allocates a 2nd string of minimum length and copies first X characters of 1st string to the 2nd string and returns the 2nd string.

What would be the correct code for that?

Some combination of malloc() and strncpy().

Why don't you try it for yourself first?
We don't typically hand out code without you making an effort first.