Given relation aRb is defined only when, both a & b are not even or odd at a time.
i.e., if a is even & b is odd then aRb is well defined.
(i) Let a and be odd and even then aRb is defined and aRb ⇒ bRa
Hence, R is symmetric.
(ii) Let a be an odd then aRa is not defined and a be an even then also aRa is not defined.
So, R is not reflexive.
(iii) Let a and b be odd and even respectively. Then if R is transitive, then aRb, bRa ⇒ aRa but, then aRa is not defined as a is odd. Hence, R is not transitive.