With Reference to Base Cross-Linking, Which, If Any, of the Following

With reference to base cross-linking, which, if any, of the following statements, is false?

A) Base cross-linking means that covalent bonds form between two bases.
B) The cross-linked bases are on opposing DNA strands.
C) The anti-cancer agent cisplatin causes a type of cross-linking between two guanine residues.
D) Pyrimidine dimers are a type of base cross-linking that is commonly induced by excess exposure to sunlight.