Final answer:
The functions from Z to Z (integers to integers) are A. f(x) = 2x and B. f(x) = x^2.
Step-by-step explanation:
The functions that are from Z to Z (integers to integers) are A and B.
In function A, f(x) = 2x, we can see that for any integer value of x, the output will also be an integer (the result of multiplying an integer by 2).
In function B, f(x) = x^2, x could be any integer, and when we square an integer, we get another integer.