(b) R is reflexive and transitive but not symmetric.
Explanation::
Let R be the relation with set {1,2, 3,4}, given by R = {(1,2), (2,2), (1,1), (4,4), (1,3), (3,3), (3,2)}.
(a) (1, 1), (2, 2), (3, 3), (4, 4) ∈ R ⇒ R is reflexive.
(b) (1, 2) ∈ R but (2, 1) does not belongs to R.
∴ R is not symmetric.
(c) If (1, 3) ∈ R and (3, 2) ∈ R, then (1, 2) also ∈ R.
∴ R is transitive.