The numbers that are integers from the options provided are:
- 15
- 2
- −34
The other options, "1 fifth" (which is \( \frac{1}{5} \)), "negative 3 fourths" (which is \( -\frac{3}{4} \)), and "4 23" (which is not clear but if it implies a fraction or mixed number, it is not an integer) are not integers.
Therefore, the integer responses are 15, 2, and −34.