Let $$R = \{(x, y) : x, y \in N$$ and $$x^2 - 4xy + 3y^2 = 0\}$$, where N is the set of all natural numbers. Then the relation R is :

A

reflexive but neither symmetric nor transitive.

B

symmetric and transitive.

C

reflexive and symmetric.

D

reflexive and transitive.