`{:("List - I (Vitamines)","List - II (Chemical names)"),((A) B_(1),"(p) Biotin"),((B) B_(2),"(q) Pyridoxine"),((C ) B_(6),"(r ) Thiamin"),("(D) H or vitamin B - 7","(s) Lactoflavin"):}`

Explanation

To solve the question, we need to match the vitamins listed in List I with their corresponding chemical names in List II.

### Step-by-Step Solution:

1. **Identify Vitamin B1**:
- Vitamin B1 is known as **Thiamine**.
- Therefore, we can match:
- (A) B1 → (r) Thiamin

2. **Identify Vitamin B2**:
- Vitamin B2 is known as **Lactoflavin**.
- Thus, we can match:
- (B) B2 → (s) Lactoflavin

3. **Identify Vitamin B6**:
- Vitamin B6 is known as **Pyridoxine**.
- Hence, we can match:
- (C) B6 → (q) Pyridoxine

4. **Identify Vitamin H or B7**:
- Vitamin H or B7 is known as **Biotin**.
- Therefore, we can match:
- (D) H or vitamin B7 → (p) Biotin

### Final Matching:
- (A) B1 → (r) Thiamin
- (B) B2 → (s) Lactoflavin
- (C) B6 → (q) Pyridoxine
- (D) H or vitamin B7 → (p) Biotin

### Summary of Matches:
- A → r
- B → s
- C → q
- D → p