Which, if any, of the following statements is false?

• A. Most of the inherited changes in our DNA arise because of exposure to extracellular mutagens, including radiation sources and chemical mutagens
• B. Most of the inherited changes in our DNA arise because of unavoidable endogenous errors in cellular mechanisms and harmful effects of certain natural molecules and atoms within our cells.
• C. Errors in DNA replication and DNA repair are a major source of mutations in our cells
• D. Significant chemical damage is sustained by DNA because of its proximity to water molecules in our cells.