Question 133
Giovanni draws in pencil a regular 9-gon and connects each of its vertices to the centre, drawing a total of 18 segments and thereby obtaining nine triangles. He then goes over some of the drawn segments in pen, in such a way that in the end each of the nine triangles has exactly one side gone over in pen. In how many ways can Giovanni choose the set of segments to go over? (Note: two sets of segments obtained from one another by rotation or by symmetry are to be considered distinct.)
(A) 49
(B) 65
(C) 74
(D) 76
(E) 85
(A) 49
(B) 65
(C) 74
(D) 76
(E) 85