Exceptionally large chromosome is :-

Options

A. Lampbrush chromosome
B. Polytene chromosome
C. Megachromosomes
D. All of the above

Answer

To solve the question "Exceptionally large chromosome is:", we need to analyze the options provided and identify which types of chromosomes are considered exceptionally large.

### Step-by-Step Solution:

1. **Identify the Options**: The question likely provides options such as Lambrush chromosome, Polytene chromosome, Megachromosome, and possibly others.

2. **Evaluate Lambrush Chromosome**:
- **Definition**: Lambrush chromosomes are known for being transcriptionally active and are found in the oocytes of certain organisms.
- **Size**: They are exceptionally large due to their structure and function.
- **Conclusion**: Lambrush chromosome is indeed a type of exceptionally large chromosome.

3. **Evaluate Polytene Chromosome**:
- **Definition**: Polytene chromosomes are formed by the replication of chromosomes without cell division, leading to many copies of the chromosome.
- **Size**: They are often referred to as giant chromosomes due to their large size.
- **Conclusion**: Polytene chromosome is also a type of exceptionally large chromosome.

4. **Evaluate Megachromosome**:
- **Definition**: Megachromosomes are found in certain plants, such as tobacco, and are characterized by their large size.
- **Size**: They are indeed large chromosomes.
- **Conclusion**: Megachromosome is another type of exceptionally large chromosome.

5. **Consider the Final Option**:
- **All of the Above**: Since all the previous options (Lambrush, Polytene, and Megachromosome) are considered exceptionally large chromosomes, the correct answer to the question is "All of the above".

### Final Answer:
The answer to the question "Exceptionally large chromosome is:" is **All of the above**.