Question

"for non-experimental study designs, the approach that will likely optimize our ability to understand how the attitudes of particular individuals change over time is the"

Answer 1

This is called "Panel Study".

Panel studies are a specific outline of longitudinal investigation in which the unit of examination is taken after at indicated interims over a long time, usually for numerous years. The key element of Panel studies is that they gather rehashed measures from a same sample at various times. Most Panel studies are intended for quantitative examination and utilize structured survey information.