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
During mixed dentition stage, which of the following appliance should be used as a space maintainer for missing primary molars in mandibular arch: 
Select and explain. 
A. Distal shoe, B. Nance holding arch, C. Passive lingual arch, D. Removable functional acrylic
C: Passive lingual arch
Answer: C: Passive lingual arch 
Explanation: None