The correct option is D A, B, C and D
Nitrogen is an essential element for all forms of life. It is a component of amino acids, proteins (structural as well as functional (enzymes) components of a cell), nucleic acids, in the energy transfer molecule like adenosine triphosphate and other cell constituents. So, nitrogen is one of the fundamental requirements for cell growth and proliferation. Hence, nitrogen is the fundamental structural unit of every cell organelle as well.
In the question, given structures are:
A- RER
B- RER
C- Mitochondrion
D- Plastid
Hence, nitrogen obtained from source be it radioactive and would become part of every cell organelle, making option d the correct answer.