To solve this question, we need to match the research types listed in Set I with their corresponding nature and characteristics given in Set II. Let's analyze each option:

1. Experimental research (a) - This involves manipulating an independent variable to observe its effect on a dependent variable while controlling extraneous variables. Thus, it matches with (v) in Set II: "Controlling the extraneous variables and observing the effect of independent variable manipulated by the researcher on dependent variable."
2. Expost facto research (b) - This type of research looks for causal relationships by analyzing a situation retrospectively. Thus, it matches with (iii) in Set II: "Getting at causal facts by retrospective analysis research."
3. Participant observation based research (c) - This method involves the researcher becoming a part of the group being studied to gain a deeper understanding of their perspectives. Thus, it matches with (ii) in Set II: "Emphasizing the access to reality by sharing the perspectives of people."
4. Grounded theory approach based (d) - In grounded theory research, theories are generated or constructed from data that is systematically gathered and analyzed. The generalizations follow the observations. Thus, it matches with (i) in Set II: "Generalizations follow rather than precede the observations in due course."

Now, we match these findings to the given options:

• Correct answer: (a)-(v), (b)-(iii), (c)-(ii), (d)-(i)

Let's eliminate the incorrect options:

• Options suggesting: (a)-(ii) or (a)-(iii) or (a)-(i) do not correctly match the nature of experimental research.
• Similarly, options suggesting anything other than (b)-(iii), (c)-(ii), (d)-(i) are incorrect based on the explanation above.

Therefore, the correct match of Set I with Set II based on their characteristics and nature is (a)-(v), (b)-(iii), (c)-(ii), (d)-(i).