In the two lists given below, List I provides the types of research methods, while List II indicates the critical features associated with them. Match the two lists and choose the correct answer from the code given below.

List I (Research methods)                       List II (Critical features)

(a) Ex-post facto method                       (i) Finding out the status based on a study of a large sample

(b) Case study method                          (ii) Interpretation of thoughts of a great thinker

(c) Philosophical method                       (iii) Intervention based ameliorative approach

(d) Descriptive survey method              (iv) Causal comparison and correlational studies

                                                              (v) In-depth study of a unit specified for the purpose

Code:   (a)        (b)        (c)        (d)