Halophiles on Greek means "salt-loving", so organisms that belong to this group are extremophiles (survive in extreme environment) that live in high salt concentration. Halophiles usually belong to Archaea, but can be found in Bacteria domain and sometimes even Eukarya.
Halophiles can survive on very salty environments (with a concentration of salt that is five times greater than the salt concentration of the ocean.
Out of the choices given, the reason why Kathy's body feels sore and she has pain in her limbs after vigorously exercising is an accumulation of lactic acid in the muscles of her limbs. The correct answer is A.