Hi,
Try with the below it might work.
Article A need to create under Article category Structured article (sales set), adding components in to that, before creating article A need to set up all components article Cand D as single article, all components inventory should maintain at site/store level.
When you sell the article A, the proportionate quantity of components inventory will be reduced based on the aticle A sales quantity.
you can sell components articles saparately as well.
for Example
Artcile A unit of measure EA = artcile C (each) + artcile D (each)
Regards,
ThirumalR
