This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Death and postmortem changes, Subject name: Forensic Medicine
Instantaneous rigor is seen in - 
Select and explain. 
A. Cadaveric spasm, B. Rigor mois, C. Cold stiffening, D. Gas stiffening
A: Cadaveric spasm
Answer: A: Cadaveric spasm 
Explanation: Cadaveric spasm is stiffness and rigidity of muscles immediately after death without moving into primary relaxation. Dr. Narayana Reddys Synopsis of Forensic Medicine & Toxicology 27 th edition pg. 81.