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: Surgery
Thermoregulatory response activated by cold is- 
Select and explain. 
A. Cutaneous vasodilatation, B. Anorexia, C. Increased voluntary activity, D. Increased respiration
C: Increased voluntary activity
Answer: C: Increased voluntary activity 
Explanation: * In cold environment, muscular contractions are increased and there is increased heat production Increased muscular contraction can be due to: 1) Increased tone of muscles. 2) Voluntary activities like foot stamping, hand rubbing, spoing activities etc. * Hypothalamic stimulation in cold environment brings about the following effects which help against cold- 1) Cutaneous vasoconstriction. 2) Shivering (involuntary muscular contractions). 3) Horripilation / Piloerection (standing up of body hair). 4) Adipose tissue lipolysis (generates heat).