The correct answer is A. type : breed.
A Siamese is a type of cat. A dog is a type of animal. A puppy is a young dog. A mark is a spot on something. Romaine is a type of lettuce. A collar is an accessory worn around the neck of an animal. A leash is a piece of equipment used to control an animal.
The relationship between Siamese and cat is that Siamese is a type of cat. The relationship between dog and puppy is that dog is a type of animal and puppy is a young dog. The relationship between mark and spot is that mark is a spot on something. The relationship between romaine and lettuce is that romaine is a type of lettuce. The relationship between collar and leash is that collar is an accessory worn around the neck of an animal and leash is a piece of equipment used to control an animal.
Of the five options, only A, type : breed, has the same relationship as the original pair of words.