A chordate character is

Options

A. gills
B. spiracles
C. post-anal tail
D. Chitinous exoskeleton

Explanation

### Step-by-Step Solution:

1. **Understanding Chordate Characteristics**:
- Chordates are a group of animals that share certain key characteristics at some stage of their development. These include a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

2. **Identifying the Options**:
- The options provided are gills, sparracas, post-anal tail, and catanus exist. We need to determine which of these is a characteristic of chordates.

3. **Analyzing Each Option**:
- **Gills**: While many chordates (especially aquatic ones) have gills, they are not a defining characteristic of all chordates.
- **Sparracas**: This term does not relate to any known chordate characteristic.
- **Post-anal tail**: This is a definitive characteristic of chordates. It is present in all chordates at some stage of their development and serves various functions, such as locomotion.
- **Catanus exist**: This term does not correspond to any known characteristic of chordates.

4. **Conclusion**:
- Among the given options, the post-anal tail is the most significant characteristic of chordates. Therefore, the correct answer is the post-anal tail.

### Final Answer:
The chordate character is the **post-anal tail**.