Answer:
B. Rough endoplasmic reticulum.
Explanation:
Antibodies are proteins, and as well as most other proteins are produced by ribosomes on the rough endoplasmic reticulum. It is note worthy that the immune system cells are responsible for the production of this antibodies, not all cells in our body. The immune system is comprised by two main cell types: B cells and T cells, and B cells are majorly responsible for the production of antibodies.