Which one of the following is an example of negative feedback loop in humans ?

Question

( A ) Secretion of sweat glands and constriction of skin blood vessels when it is too hot
( B ) Constriction of skin blood vessels and contraction of skeletal muscles when it is too cold
( C ) Secretion of tears after falling of sand particles into the eye
( D ) Salivation of mouth at the sight of delicious food