Which one of the following statements about the immune system is true? A. Recombination of genes to produce functional B-cell receptors occurs immediately after exposure to antigen. B. Helper T-cells bind to type I MHC proteins and cytotoxic T-cells bind to type II MHC proteins. C. The major histocompatibility complex codes for a large group of cell surface glycoproteins. D. Plasma cells secrete IgM molecules early, and then IgD molecules later. E. Interferons specifically protect body cells against attack by parasites.

The correct answer is option C. "The major histocompatibility complex codes for a large group of cell surface glycoproteins".

Explanation:

The major histocompatibility complex (MHC) refers to a large group of cell surface glycoproteins, essential to  the adaptive immune system. T cell receptors of the immune system expose antigens to specific MHC complexes, which leads to proliferation of T cells that have a key role in the adaptive immune system. The T cell receptors interact with the MHC class I and class II glycoproteins during this process.

i am going to guess that it is co2.