Step 1: Analyzing the diseases.
We need to match each disease from Column-I with its causative agent from Column-II. Let's review each disease and its corresponding causative organism.
Step 2: Analyzing the options.
(a) Acute coryza: Acute coryza is caused by Rhino viruses, making the correct match (a-iv).
(b) Pneumonia: Pneumonia is caused by Streptococcus bacteria, making the correct match (b-iii).
(c) Dermathophytosis: Dermathophytosis, or fungal skin infection, is caused by Microsporum, making the correct match (c-ii).
(d) Elephantiasis: Elephantiasis, caused by Wuchereria, is a parasitic infection leading to swollen limbs, making the correct match (d-i).
Step 3: Conclusion.
The correct answer is (D) a-iv, b-iii, c-ii, d-i, as these are the correct matches for the diseases and their causative agents.