The correct option is B They show contact inhibition.
Cancer is a group of disease, that involves abnormal cell growth (abnormal cell division), with the potential to invade or spread to other parts of the body. They compete with normal cells for nutrients. Contact inhibition is a growth mechanism, which functions to keep cells from growing into a layer one cell thick or monolayer. The cancer cells do not show contact inhibition and they grow uncontrollably.
Thus, the correct answer is option (D), 'They show contact inhibition'.