Please help me with this coding problem :) Consider the following field and incomplete method of some class. The method calcTotal is intended to return the sum of all values in vals.

private int[] vals;

public int calcTotal()
{
int total = 0;

/* missing code */

return total;
}
Which of the code segments shown below can be used to replace /* missing code */ so that calcTotal will work as intended?

I.
for (int i : vals)
{
total += i;
}
II.
for (int pos = vals. length; pos > 0; pos--)
{
total += vals[pos];
}
III.
int pos = 0;
while (pos < vals. length)
{
total += vals[pos];
pos++;
}

I only
II only
I and III
II and III
III only