[Spiritual]

Which of these are not carboxylic acid derivatives

CH3CH2CH2COCl

C6H5OCH3

CH3CONHCH3

CH3CO2CH3

[Babcock_Hall]

Try drawing out the structures; it will be easier.

[Aldebaran]

Do you know what a carboxylic acid derivative is…or is that what your underlying question is?
There are a few of your questions in different places on this forum which relate to naming of organic compounds and this gives the impression you are unfamiliar with organic nomenclature. You would probably benefit from an introductory text which explains some of the basic nomenclature rules in a structured way rather than throwing up what appear to be random test questions.

[hollytara]

There is only one that is not....

You should get the nomenclature book by Traynham if it is still in print. 

And the book by Fredlos for introduction to organic.