“It begins as a single cell and grows into a merciless disease that claims millions of lives year after year. But scientists are steadily unlocking its mysteries, and the fight against it may now have reached a dramatic turning point. New discoveries promise better therapies and hope in the war against ...” The disease referred to in the above quotation is

The correct answer is A because the description perfectly matches the biological nature and clinical progression of cancer. Cancer typically begins with a single cell that undergoes genetic mutations, leading to uncontrolled growth and division. Unlike many other diseases, it is characterized as a merciless growth of the body s own cells that spreads to other tissues. The reference to a turning point and new discoveries relates to recent breakthroughs in immunotherapy and targeted genetic treatments which have fundamentally changed the outlook for cancer patients in ways that differ from the management of viral or bacterial diseases like AIDS or Tuberculosis.