Which of these messages most effectively conveys empathy in a bad-news message?

A、You have every right to be disappointed. I am truly sorry that our product failed to perform as expected.;
B、I am deeply saddened that your service failure disrupted our sale, and we will do everything in our power to improve our future performance.;
C、We did not intentionally delay the shipment, and we will not accept the disappointment and frustration you have expressed.;
D、It is with great regret that we must take this step, but you have left us no choice.