Take it as a challenge .Let's see who can do this.

ans: C

So ishan ur ans is correct.Pleasse post me the solution aince i don't know how to solve it.

Is this method correct.Don't know the mechanism.

symmetry works for me in max no of questions

remember if a path is extremely long and twisted there exists another path connected to the begining u just need to find it

yaar C mein cyclopropane groups ko ulta nahi laga diya tumne manmay? This is Simmons-Smith reaction, iska mechanism fully clarified nahi hai, a carbene or carbenoid is supposed to be involved. It is used to form cyclopropane rings from alkenes.
I mean the triangles will have their base on the carbon chain, and not their vertices on the chain, if you get what I mean.

simply carbenoid will react to form ring

That was exactly my point....tapas is right.
I was looking for the mech, and found it in my fiitjee package. its the same.