It is given that the sum of two integers is 10, which is a positive integer.
But, we know that the sum of two negative integers is always a negative integer.
So, if the sum of two integers is positive and one of them is negative, then the other has to be positive.
For example,
−2 + 12 = 10
−5 + 15 = 10
Thus, the other integer has to be positive.
Hence, the correct answer is option (b).