According to Super and Harkness, there are several methods that are suitable for studying components of the developmental niche. They include a. participant observation, diaries, and ethnographic interviews. b. quasi-experimentation, controlled experimentation, and structured questioning. c. controlled experimentation, spot observations, and longitudinal data. d. none of the above are suitable methods

a. participant observation, diaries, and ethnographic interviews.

Explanation:

Participant observation: The term participant observation is defined as a method of qualitative research in which the experimenter observes the participants or subjects involved in the research as well as the experiment actively engages or involved in their activities.

Ethnographic interview: The term ethnographic interview is defined as a method of qualitative research that involves one-on-one interviews and immersive observation.

Diaries: The diary research is a form of qualitative research method that involves collecting qualitative data of the participants' activities, behaviors, and experiences over a period.

In the question above, since Super and Harkness are studying a developmental niche that can not be calculated or is an empirical variable, so it would be better for them to use qualitative methods to study. Therefore, it includes participant observation, diaries, and ethnographic interviews.