I'm tutoring few Class 12 students for their chemistry exams. I'm stuck with few problems. I don't know, if the key is wrong or I am wrong.
Answer According to me:
Product (A) must be the cyclic diene, as given in option (A). Now, I don't know, what happens when you heat cyclic diene with selenium. But I do know that, $SeO_2$ oxidizes allylic position of alkene into alcohol. But, none of the options given are fitting into that argument
Answer given in the book: