Identify the type of observational study​ (cross-sectional, retrospective, or​ prospective) described below.
A research company uses a device to record the viewing habits of about 5000 households, and the data collected over the next 10 years will be used to
determine whether the proportion of households tuned to a particular educational program decreases.
Which type of observational study is described in the problem​ statement?

a) a retrospective study
b) a prospective study
c) a cross-sectional study