JEE Math Practice Question

Let $$R_{1}$$ and $$R_{2}$$ be two relations defined on $$\mathbb{R}$$ by $$a \,R_{1} \,b \Leftrightarrow a b \geq 0$$ and $$a \,R_{2} \,b \Leftrightarrow a \geq b$$ Then,

1. A.$$R_{1}$$ is an equivalence relation but not $$R_{2}$$
2. B.$$R_{2}$$ is an equivalence relation but not $$R_{1}$$
3. C.both $$R_{1}$$ and $$R_{2}$$ are equivalence relations
4. D.neither $$R_{1}$$ nor $$R_{2}$$ is an equivalence relation