The administration at the University of Nebraska in Lincoln is interested in student reaction to a planned parking garage on campus. A dormitory near the proposed site is selected and several Student Senate members volunteer to solicit responses. One Thursday evening, the volunteers each take a specific dorm wing, knock on doors, and record student answers to several prepared questions. Is this an observational study or an experimental study

observational study

Explanation:

Observational study: In psychological research, the term "observational study" is described as a study in which a researcher tends to observe the effect of treatment, risk factor, diagnostic test, or some other intervention in the absence of any efforts to change who is or is not exposed from the same.

In other words, a researcher tends to capture data based on what subjects or participants do as in opposition to what they say they'll do.

In the question above, the given statement represents "observational study".

the answer to your question is,

d. when a child was born.

-mabel < 3