Which of the following compounds will give a three-membered cyclic ether (epoxide) when treated with aqueous NaOH, by intramolecular SN2 ring closure of the alkoxide? (Consider only this ring-closure pathway.)

The alkoxide must attack the C-Cl carbon from the back, so the O and Cl must be anti, and the ring formed must be three-membered. 2-Chloroethanol qualifies, and the trans-chlorohydrin reaches the diaxial arrangement. The cis-chlorohydrin never achieves an anti relationship. 4-Chlorobutan-1-ol cyclises to a five-membered ring (tetrahydrofuran), not to an epoxide.