Counterparty credit risk refers to the risk that the counterparty to a financial contract will default before the final settlement of the contract's cash flows, resulting in a financial loss. This is correctly stated in option A.

The exposure at default (EAD) is indeed variable due to fluctuations in the underlying valuations, such as swaps, as mentioned in option B.

The EAD can be negatively correlated with the probability of default (PD) because as the credit quality of a counterparty deteriorates, their exposure may also decline, correctly stated in option C.

However, dynamic collateral provisions are typically designed to reduce counterparty risk by adjusting collateral requirements based on changes in exposure and credit quality, not to increase it. Therefore, option D is incorrect.