18. Grignard reagents react with oxirane (ethylene oxide) to form 1o-alcohols but can be prepared in tetrahydrofuran solvent.Why is this difference in behavior observed? 
(A) Steric hindrance in the case of tetrahydrofuran precludes reaction with the Grignard. 
(B) There is a better leaving group in the oxirane molecule.
(C) The oxirane ring is the more highly strained. 
(D) It is easier to obtain tetrahydrofuran in anhydrous condition. 
(E) Oxirane is a cyclic ether, while tetrahydrofuran is a hydrocarbon.