Which statement is most appropriate?

The formal police caution in the UK runs as follows:

a. You do not have to say anything. But it may harm your defence if you do not mention something which you may later rely on in court. Anything you do say may be given in evidence.

b. You do not have to say anything. But anything you do say may be given in evidence.

c. You do not have to say anything. But it may harm your defence if you do not mention something which you may later remember. Anything you do say may be given in evidence.

d. You do not have to say anything. But it may harm your defence if you do not mention something which you may later rely on in court. Anything you do say will be written down and used by the prosecution.