Under which provision does the claimant claim interest according to a written contract from a specified date?

The correct choice highlights that when a claimant seeks interest under a written contract, it is most appropriately grounded in a specific clause within that contract itself. Contracts often include specific provisions that detail how and when interest on overdue amounts should be calculated and applied, including the start date for that interest.

This is a crucial aspect of contract law, where parties outline their agreement and stipulate important terms. When the claim for interest arises from the terms established within the contract, the reference to "clause X" indicates that the parties had a mutual understanding regarding interest that is enforceable as part of that contract. Hence, if a party is claiming interest as per a written agreement, citing the relevant clause directly aligns with the principles underpinning contractual obligations and enforcement.

The other options, while they pertain to the overall context of interest claims, do not specifically address the direct and explicit contractual basis for such a claim. For example, reference to statutory provisions like the Late Payment of Commercial Debts Act may apply in certain situations but does not substitute for the explicit terms agreed upon by the parties in their contract. Also, general provisions of the Civil Procedure Rules or the Senior Courts Act may provide broader frameworks for claiming interest, but they do not replace a specific contractual stipulation