A Pen can be without Tube, Ink, Holder and Cap.

Correct Option: E

A Pen cannot be without Nib. A Pen can be without Tube, Ink, Holder and Cap. So a pen have always the mandatory component is NIB.

A bulb can be without Light , Glass, Current and argon.

Correct Option: A

A bulb can be without Light , Glass, Current and argon. A bulb always have a filament.

A camera can be without Reels, Stand, Photograph and Flash.

Correct Option: A

A camera can be without Reels, Stand, Photograph and Flash. A camera is no use without the lens. So A camera cannot use without lens.

River can be without Delta , Tributaries , Boats and fishes.

Correct Option: D

River can be without Delta , Tributaries , Boats and Fishes. A river can be called river without Banks. So banks are the mandatory for a river.

A factory can run without electricity and with coal power or with any other power sources. Chimney is not mandatory for a factory. File are also not mandatory component for factory. Sellers are required but not mandatory.

Correct Option: C

A factory can run without electricity and with coal power or with any other power sources. Chimney is not mandatory for a factory. File are also not mandatory component for factory. Sellers are required but not mandatory. The most important component for factory is workers. If workers will be not there then factory will be shutdown and will not called factory without workers.