The correct answer is C. base : ball.
A petal is a part of a flower, while a base is a part of a ball. A petal is typically a colorful, leaf-like structure that surrounds the reproductive parts of a flower. A base is the bottom part of something, such as a ball. It is the part that supports the weight of the object and keeps it from rolling away.
The other options do not have the same relationship as the original pair of words. Salt and pepper are both spices, but they are not parts of the same thing. A tire is a part of a bicycle, but it is not the same as a bicycle. Sandals are a type of shoe, but they are not the same as a shoe. A puppy is a young dog, but it is not the same as a dog.