Final Answer:
Leukopenia is indicated by WBC levels of <5000/mL.
Therefore, correct option is A. <5000/mL.
Step-by-step explanation:
Leukopenia refers to a decrease in the total white blood cell (WBC) count. The threshold indicating leukopenia is typically considered to be a WBC level below 5000/mL (A). This condition can result from various causes, such as infections, autoimmune disorders, medications, or bone marrow disorders, leading to an increased risk of infections due to compromised immune function.
Monitoring WBC levels is crucial in assessing immune system health. A WBC count below 5000/mL may prompt further investigation into the underlying cause and appropriate interventions to address the specific condition contributing to leukopenia.
Therefore, correct option is A. <5000/mL.