Unobstructive research differs from other survey research in that a. it's often employed to everly the effects of social programs b it can be carried on without concern for random sampling c it doesn't have an impact on the subject being studied d. it can produce longitudinal data that permits relations among many variables

Unobstructive research differs from other survey research in that C. it doesn't have an impact on the subject being studied.

Rationale:

Unobstructive research involves the method of collecting data wherein the researcher is physically not present in front of the subject. The reason being that the subjects may alter there behaviour towards the researcher and it may affect the nature of the colected data.

The answer is option C.

Explanation:

Obstructiveness research includes the technique for gathering information wherein the scientist is physically not present before the subject. The reason being that the subjects may modify there conduct towards the specialist and it might influence the idea of the collected information.

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explanation: