Final answer:
The correct statement about immunodeficiency is that the causative agent in acquired immune deficiency syndrome (AIDS) is a virus that recognizes helper T (CD4) cells.
Step-by-step explanation:
The correct statement about immunodeficiency is B. The causative agent in acquired immune deficiency syndrome (AIDS) is a virus that recognizes helper T (CD4) cells.
AIDS is caused by the human immunodeficiency virus (HIV), which specifically targets and infects CD4+ T cells. This virus weakens the immune system and leads to the development of opportunistic infections and cancers.
Therefore, option B is the correct statement regarding immunodeficiency.