The classification category below the level of family is :

Options

A. class
B. genus
C. phylum
D. species

Explanation

To solve the question regarding the classification category below the level of family, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Taxonomic Hierarchy**:
- Taxonomy is the science of classification of living organisms. It has a hierarchical structure that includes several ranks such as domain, kingdom, phylum, class, order, family, genus, and species.

2. **Identifying the Rank Below Family**:
- In the taxonomic hierarchy, the rank that comes immediately below the family is the genus.

3. **Definition of Genus**:
- A genus is a group of species that are closely related and share a common ancestor. It is a higher taxonomic rank than species and is used to classify organisms based on shared characteristics.

4. **Criteria for a Genus**:
- A genus must fulfill certain criteria to be descriptively useful:
- **Monopoly**: All descendants of an ancestral taxon are grouped together.
- **Reasonable Compactness**: A genus should not be expanded unnecessarily.
- **Disintent with Respect to Relevant Criteria**: This includes ecological, morphological, and biogeographical considerations.

5. **Examples of Genus**:
- An example of a genus is "Rosa," which includes many species of roses.
- Another example is "Ginkgo," which is monotypic, containing only the species Ginkgo biloba.

### Final Answer:
The classification category below the level of family is **Genus**.

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