Answer:
b. The researcher has not ruled out the possibility that Y might cause X
Step-by-step explanation:
In the given system, there is a theory that shows the relationship between the variables 'X' and 'Y'. The variable 'X' shows life satisfaction in a given population while the variable 'Y' shows how stable a democratic institution is. Therefore, the occurrence of the variable 'Y' can lead to the occurrence of the variable 'X'.