Lauren, a social psychologist, hypothesizes that the best way for a young woman to increase the number of friends she has on a social networking site is to place a smiling display picture in her profile. lauren wants to establish a cause-effect relationship between these two variables. in order to accomplish her objective, lauren should use:
a, a survey
b, correlational research
c, experimental research
d, an interview

C. Experimental research        

Explanation:

Experimental research design (ERD)- It is a study that strictly stick to scientific research design. This comprises variables that can be calculated, compared and measured, a hypothesis and a variable to be manipulated by the experimenter. An experimental research design is completed only in a controlled environment.

There are three types of ERD:

1. Quasi-experimental design.

2. Pre-experimental design.

3. True experimental design.

Experimental research design is quantitative in nature.

you should think about the answers you give and expect the same form your questions.