Let $$R$$ be a relation on $$\mathbb{R}$$, given by $$R = \{(a, b) : 3a - 3b + \sqrt{7} \text{ is an irrational number}\}$$. Then $$R$$ is

A

Reflexive but neither symmetric nor transitive

B

Reflexive and transitive but not symmetric

C

Reflexive and symmetric but not transitive

D

An equivalence relation