According to the given image, the tree diagram begins with Real Numbers.
The second level is formed by subsets of Real Numbers which are Rational Numbers and Irrational Numbers.
The third level is formed by subsets of rational numbers which are Non-Integer Rational Numbers and Integer Rational Numbers.
This means the missing part must be filled with Integer Rational Numbers.
Therefore, the right answer is -7, 8, -4, because these numbers are rational integers.