`{:(,,"Column I","Column II"),(,I,"Methaogens","A. Microbial bicontrol agent"),(,II,"Organic wastes","B. Penicillin"),(,III,"Bacillus thuringiensis","C. Biochemical oxygen demand"),(,IV, "Penicillin notatum","D. Methanobacterium"):}`
Which of the combination is correct?

Options

A. I-B, II-A, III-D, IV-C
B. I-C, II-D, III-A, IV-B
C. I-D, II-C, III-A, IV-B
D. I-D, II-B, III-A, IV-C

Answer

To solve the question of matching items from Column I with their corresponding items in Column II, we will analyze each item in Column I and find the correct match from Column II.

### Step-by-Step Solution:

1. **Identify Methanogens**:
- Methanogens are microorganisms that produce methane as a metabolic byproduct in anoxic conditions. They are commonly found in environments rich in organic materials, such as swamps and the intestines of animals.
- **Match**: Methanogens → Methanobacterium (D)

2. **Identify Organic Wastes**:
- Organic wastes refer to biodegradable waste materials that can be broken down by microorganisms. The decomposition of organic waste is often measured by Biological Oxygen Demand (BOD), which indicates the amount of oxygen required by aerobic microorganisms to decompose organic matter.
- **Match**: Organic wastes → Biochemical Oxygen Demand (C)

3. **Identify Bacillus thuringiensis**:
- Bacillus thuringiensis (Bt) is a bacterium that is used as a microbial biocontrol agent. It produces toxins that are harmful to certain insects, making it useful in agriculture as a natural pesticide.
- **Match**: Bacillus thuringiensis → Microbial biocontrol agent (A)

4. **Identify Penicillin notatum**:
- Penicillin notatum is a mold that produces penicillin, the first widely used antibiotic. It was discovered by Alexander Fleming and is used to treat various bacterial infections.
- **Match**: Penicillin notatum → Penicillin (B)

### Final Matches:
- Methanogens → Methanobacterium (D)
- Organic wastes → Biochemical Oxygen Demand (C)
- Bacillus thuringiensis → Microbial biocontrol agent (A)
- Penicillin notatum → Penicillin (B)

### Conclusion:
The correct combinations are:
1. Methanogens - D (Methanobacterium)
2. Organic wastes - C (Biochemical Oxygen Demand)
3. Bacillus thuringiensis - A (Microbial biocontrol agent)
4. Penicillin notatum - B (Penicillin)

Therefore, the correct answer is option 3.