This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hospital waste and disaster management, Occupational health, Subject name: Social & Preventive Medicine
All of the following are true for occupational lead poisoning except - 
Select and explain. 
A. Inhalation is the most common mode of absorption, B. Lead in blood and urine provide quantitative indicators of exposure, C. Average blood is more impoant than number of subjects with blood levels above threshold, D. Basophilic stippling is a sensitive parameter of hematological response
C: Average blood is more impoant than number of subjects with blood levels above threshold
Answer: C: Average blood is more impoant than number of subjects with blood levels above threshold 
Explanation: Lead poisoning occurs as inhalation and ingestion.Measuremwnts of lead in blood and urine provide quantitative indicators of exposure.Lead in urine of over 0.8mg/litre indicates lead exposure.A blood level of 70microgram/100 ml is associated with clinical symptoms.Basophilic stipling of RBC is a .sensitive parameter of the haematological response.(Ref.PARK'S textbook of preventive and social medicine 21st edition page no.748,749)