Natural history of some chronic diseases may be described by iceberg phenomenon. Floating tip represents what the physician sees in clinical practice and submerged portion of the iceberg represents subclinical cases, carriers and undiagnosed cases. Essential purpose of screening test for a chronic disease is to identify -

• A. The floating tip of iceberg
• B. Hidden portion of iceberg
• C. Both floating tip and hidden portion
• D. Complication of disease