The correct option is C contact inhibition
Contact inhibition is a property of a normal cell which inhibits the uncontrolled growth of the nearby sorrounding cells. Cancer cells appears to have lost this property. As a result of this, cancerous cells just continue to divide giving rise to masses of cells called tumors.
Metastasis is the spread of cancer cells to new areas of the body, often by way of the lymph system or bloodstream.
A carcinogen is any substance that promotes carcinogenesis, the formation of cancer.
An oncogene is a gene that has the potential to cause cancer.