Which organic structure among the following is not an isomer of the compound CH_(3)-CO-CH_(2)CH_(2)CH_(2)CH_(3) ?

Which organic structure among the following is not an isomer of the co

1.	Which organic structure among the following is not an isomer of the compound CH_(3)-CO-CH_(2)CH_(2)CH_(2)CH_(3) ?
Answer» `CH_(3)CH_(2) OCH = CHCH_(2)CH_(3)` `CH_3CH=CHCH_(2)CH_2CHO` ` (CH_3)_2 CH - CO - CH_(2)CH_3` `CH_(3)CH_(2)COCH_(2)CH_(2)CH_(3)` ANSWER :B