Which Is Most Correct

Which is most correct?
The costs of either party in undertaking reasonable pre-action protocol practice guidelines are …

A) recoverable as 'incidental to' proceedings if proceedings are subsequently issued.
B) not generally recoverable within the costs of any subsequently issued proceedings.
C) generally only recoverable as part of the costs of an action subsequently issued if they were part of the detail of the claim set out in the letter of claim.
D) generally recoverable in any subsequently issued proceedings.