Among the options provided, coffee is known to have diuretic properties. Caffeine, a component of coffee, can increase urine production.
Water does not act as a diuretic; rather, it helps maintain hydration and can promote normal urine output. Milk contains some fluid, but it is not considered a diuretic. Chamomile tea may have mild diuretic effects, but it is not commonly classified as a diuretic like coffee.
So, the best answer is coffee.