Which of the following is a reason for a researcher to select a quasi-experimental design? select one:

a. to enhnace external validity.
b. to avoid the ethical issues a true experiment would cause.
c. to take advantage of real-world opportunities to study phenomena and events.
d. all of the above.

To avoid the ethical issues a true experiment would cause.

Explanation:

A quasi-experiment is a factual conventional study that is used to calculate the causal effect of interference on a target population without an irregular function. Quasi-experimental research shares closeness with traditional experimental design or randomized controlled trials, but lacks the element of random assignment specifically for treatment or control.

Instead, quasi-experimental designs typically allow the researcher to control the assignment to treatment status, but use some criterion other than random assignment (For example- an eligibility cutoff mark).