How did people measure speed before tech devices were invented?

Which situation is an example of an observational study?

The seventh-grade students at charleston middle school are choosing one girl and one boy for student council. their choices for girls are michaela (m), candice (c), and raven (r), and for boys, neil (n), barney (b), and ted (t). the sample space for the combined selection is represented in the table. complete the table and the sentence beneath it.

Need answer asap (see image) (20 points)