अणु सूत्र C4H10O वाले एक कार्बनिक यौगिक के लिए संभावित ईथर समावयवियों (ether isomers) की कुल संख्या कितनी होगी?

Among the following, identify the compound that is NOT an isomer of hexane (C6H14).

Consider the following statements for geometrical isomerism: 1. All geometrical isomers have a double bond. 2. All geometrical isomers are diastereoisomers. 3. All geometrical isomers have restricted rotation about a bond. 4. No two substituents on any of the atoms about which there is restricted rotation, should be the same. Of these, the correct statements are: