Among the relations
$$S = \{(a,b): a, b \in R - \{0\}, 2 + \dfrac{a}{b} > 0\}$$ and $$T = \{(a,b): a, b \in R, a^2 - b^2 \in Z\}$$,

A

$$S$$ is transitive but $$T$$ is not

B

both $$S$$ and $$T$$ are symmetric

C

neither $$S$$ nor $$T$$ is transitive

D

$$T$$ is symmetric but $$S$$ is not