The relationship between "Monster" and "Giant" is that they both represent something exceptionally large or imposing, often beyond the normal size or scale.

Let's analyze the other pairs:

(1) Tiger : Leopard - Both are large feline predators belonging to the same genus Panthera (in a broader sense, though leopard is Panthera pardus and tiger is Panthera tigris).

(2) Bull : Crocodile - These are two different types of animals with no direct size or scale relationship implied in the same way as monster and giant.

(3) Galaxy : Garden - These are vastly different in scale. A galaxy is immensely large, while a garden is relatively small. This relationship is one of extreme difference in size, the opposite of the original pair.

(4) Hope : Anguish - These are contrasting emotions, not related to size or scale.

Considering the relationship of something being exceptionally large, the pair that best fits this analogy is Tiger : Leopard. While not exactly the same as monster and giant, both tiger and leopard are large members of the cat family, with a general similarity in size and imposing nature. A giant is essentially a very large monster. Similarly, a tiger is a very large and powerful feline, much like a leopard in its general category.