An important clinical feature of a concussed tooth is:: (A) Tooth is markedly tender to percussion, (B) Tooth is displaced from the socket, (C) Evidence of haemorrhage at gingival margin, (D) Clinically crown appears shorter
Answer is A. Concussion 

Tooth is not displaced.
Mobility is not present.
Tooth is tender to percussion because of edema and hemorrhage in the periodontal ligament.
Pulp may respond normal to testing.