Envision that a particular virus, chicken pox, has just entered the body. We might need millions of B and T cells to combat this virus. But, we only have a few B cells and a few T cells currently in the body that can recognize chicken pox virus.
In a brief description, what has to happen?

The whole situation will stimulate the Adaptive Immunity system along with Humoral responses.  As the individual is lacking both B and T cells, therefore the virus will be able to make infection by causing the disease.

Explanation:

Chickenpox has a particular antigen. It will act as an epitope that interacts with the particular sites of the lymphocyte. The epitope will stimulate the Adaptive Immunity system. The antigen will activate both B and T cells.  

Here 2 cases can happen.  

d is the answer

sorry if its wrong!

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.