Which of the following functions is symmetric, but neither reflexive nor transitive?
1
R = {(T1, T2) : T1 is congruent to T2, where T is the set of triangles in a plane}
2
R = {(T1, T2) : T1 is similar to T2, where T is the set of triangles in a plane}
3
R = {(L1, L2) : L1 is parallel to L2, where L is the set of lines in a plane}
4
R = {(L1, L2) : L1 is perpendicular to L2, where L is the set of lines in a plane}