Which one of the following statements is correct with respect to salt water balance inside the body of living organisms?
(a) When water is not available camels do not produce urine but store urea in tissues.
(b) Salmon fish excretes lot of stored salt through gill membrane when in fresh water.
(c) Paramecium discharges concentrated salt solution by contractile vacuoles.
(d) The body fluids of fresh water animals are generally hypotonic to surrounding water.