Minimum should be 4. Maximum should be 30.
As explained, it's read, increment count and store(3 steps) during execution of :
3 test() calls with 5 iterations for each. For simplicity let's consider 3 processes P1, P2 and P3 will execute one test each.
P1: Test() call (first iteration): loads '0', increments it by 2, [gets preempted before storing it back]
P2: Allow all 5 iterations for test() to run. The count value will now be 10
P3: 4 iterations of third test() runs normally and gets preempted. So, now the value of count is 18.
Now, P1 is starts again from where it left off. It has count value of 2 incremented locally. It stores back 2 and gets preempted.
Now, P3 resumes execution of it's final iteration. It loads the value of count as 2, increments it to 4 and gets preemted
Now, P1 executes remaining 4 iterations making the value of count as 10.
Finally, P3 executes the 'store' for it's last iteration. It stores back 4 (since it has count value as 4 locally incremented)
So, minimum turns out to be 4
The maximum will be 30 (execution happens sequentially)