### Core Concept
The length of the maxillary cuspid is an important anatomical parameter in dentistry and orthodontics. It is a key factor in determining the aesthetics and function of the anterior teeth. The average length of the maxillary cuspid is a standard reference value used in various dental procedures.

### Why the Correct Answer is Right
The average length of the maxillary cuspid is typically measured from the incisal edge to the cemento-enamel junction. This measurement is essential in orthodontic treatment planning, as it helps in determining the optimal position of the tooth. The length of the maxillary cuspid is also a factor in the diagnosis and treatment of anterior open bite and deep bite malocclusions.

### Why Each Wrong Option is Incorrect
**Option A:** This option is likely too short, as the maxillary cuspid is generally longer than incisors. Measuring the length of the maxillary cuspid from the incisal edge to the cemento-enamel junction would yield a value higher than this option.
**Option C:** This option is likely too long, as the maxillary cuspid is generally shorter than incisors. The length of the maxillary cuspid is typically less than the adjacent central incisors.

### Clinical Pearl / High-Yield Fact
In orthodontic treatment planning, the length of the maxillary cuspid is an important factor in determining the optimal position of the tooth. A longer maxillary cuspid may require more complex orthodontic treatment to achieve optimal aesthetics and function.

### Correct Answer: 13.5 mm. The average length of the maxillary cuspid is approximately 13.5 mm.