The question asks us to match the diseases listed in List I with their corresponding deficiencies listed in List II.

List I:

A. Beriberi

B. Pellagra

C. Pernicious anemia

D. Scurvy

List II:

1. Vitamin C deficiency

2. Niacin deficiency

3. Thiamine deficiency

4. Vitamin B12 deficiency

Looking at the correct answer, option 3, we can see that it matches the diseases and deficiencies correctly:

A. Beriberi - 3 (Thiamine deficiency)

B. Pellagra - 2 (Niacin deficiency)

C. Pernicious anemia - 4 (Vitamin B12 deficiency)

D. Scurvy - 1 (Vitamin C deficiency)

Therefore, the correct answer is option 3, which correctly matches the diseases with their corresponding deficiencies.

Note: It is important to note that the provided answer is correct.