In the 1970s,a 13-Year-Old Girl Was Found Locked Up in a Room,strapped

In the 1970s,a 13-year-old girl was found locked up in a room,strapped to a potty chair.Because she had grown up in a world without human speech,researchers studied "Genie's" ability to acquire words,grammar,and pronunciation.This type of research is called ________________________ because a lot of data were gathered about a single case.

A) a case study
B) a representative sample
C) a single-blind study
D) a naturalistic observation