A researcher notices that her children eat a good nutritious breakfast on some mornings, but on other days they eat doughnuts. The researcher then observes that the children seem to have less energy...

A researcher notices that her children eat a good nutritious breakfast on some mornings, but on other days they eat doughnuts. The researcher then observes that the children seem to have less energy at mid-morning on the days they eat doughnuts. This is an example of getting research ideas from

a. theory.

b. casual observation.

c. systematic observation.

d. second-hand information.