Immediate stiffness postmortem occurs in

      A. Cadveric rigidity

      B. Cadaveric spasm

      C. Rigor mortis

      D. Algor mortis.

Answer: B. Cadaveric spasm.

Explanation: 

Rigor mortis: also called Cadaveric rigidity (option A), Death stiffening.

                     is a state of stiffening of muscles.

Cadaveric spasm: also called Instantaneous Rigor, Cataleptic Rigidity.

Algor mortis: Cooling of the body(Chill of death).