Final answer:
The dependent variable in this research study would be the number of symptoms exhibited by the subjects suffering from social anxiety.
Step-by-step explanation:
In this research study, the researcher wants to determine if taking a new antidepressant drug will decrease the symptoms of subjects suffering from social anxiety. The number of symptoms exhibited by the subjects would be the dependent variable (option a).
The dependent variable is the variable that is being affected by the independent variable, which in this case is the new antidepressant drug. The researcher is manipulating the independent variable (administering the antidepressant drug) to observe its effect on the dependent variable (symptoms of social anxiety). By measuring the changes in the dependent variable, the researcher can determine if the drug is effective in reducing symptoms.