Out of the four sentences select the most suitable sentence with respect to grammar and usage.
1
Observational learning is learning theory of psychology that describes how we learn by watching and imitating others.
2
Observational learning is a learning theory for psychology that describes how we learn in watching and imitating others
3
Observational learning is a learning theory in psychology that describes how we learn by watching and imitating others.
4
Observational learning is learning theory in psychology that describes how we learn by watching and imitating others.