This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
The eruption of mandibular permanent incisors lingual to deciduous dentition, can be perceived by the dentist as: 
Select and explain. 
A. A pathological finding, B. An arch length discrepancy, C. Normal finding, D. None of the above
C: Normal finding
Answer: C: Normal finding 
Explanation: The primary teeth may have undergone extensive root resorption and may be held only by soft tissues. 
In other instances, the roots may not have undergone normal resorption and the teeth remain solidly in place. 
The tooth buds of succedaneous teeth lie lingual to the primary teeth.
It is common for mandibular permanent incisors to erupt lingually, and this pattern should be considered essentially normal.
It is seen both in patients with an obvious arch length inadequacy and in those with a desirable amount of spacing of the primary incisors.