Which of the following is incorrect?

Options

A. Oligocheata-Pheretima
B. Hirudinea-Hirudo
C. Polycheata-Lumbricus
D. Nematoda-Ascaris

Explanation

To determine which of the following classifications is incorrect, we need to analyze each option provided in the question.

1. **Oligochaeta**: This class includes organisms like *Ferritima* and *Lumbricus*. Both of these examples are indeed members of the Oligochaeta class. Therefore, this classification is correct.

2. **Hirudinea**: This class consists of leeches, and examples include *Herudo* and *Hirudinaria*. Both of these examples are correct members of the Hirudinea class. Thus, this classification is also correct.

3. **Polychaeta**: This class includes marine worms, and common examples are *Nereis* and *Aphrodite*. However, *Lumbricus* is not a member of the Polychaeta class; it belongs to the Oligochaeta class. Therefore, this classification is incorrect.

4. **Nematoda**: This class includes roundworms, and *Ascaris* is a well-known example of a nematode. Hence, this classification is correct.

After evaluating all the options, we find that the incorrect classification is:

**Polychaeta - Lumbricus** (since Lumbricus belongs to Oligochaeta).

### Final Answer:
The incorrect classification is **Polychaeta - Lumbricus**.

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