Answer:
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.