Why Is Cancer Treated Most Successfully in Its Earliest Stages

Why is cancer treated most successfully in its earliest stages?

A) All cancers are slow-growing in their early stages which makes them more susceptible to treatment.
B) Cancer cells release toxins that can accumulate in the body over time. The earlier the treatment, the fewer of these toxins are in the body.
C) The earlier the cancer is caught, the fewer the number of cancer cells there are that need to be killed, which makes it easier for the chemotherapy and the immune system to work together.
D) Early-stage cancer cells carry genetic markers that make them easy to identify and target with both chemotherapeutics and radiation treatment.