Many Birds, Such as Seagulls, Rarely Drink Fresh Water

Many birds, such as seagulls, rarely drink fresh water. What is the main way that such birds deal with the osmotic stress of taking in large quantities of salt in their food?

A) by excreting excess salt through the actions of specialized salt glands in their heads
B) by active transport of ions into the body through their feet
C) by excreting nitrogenous wastes through their kidneys as urea
D) by maintaining high levels of urea and trimethylamine oxide in body fluids