Answered: NEC ECC: As a Contractor I want to terminate with the client should they not provide a minimum number of jobs per day, how do I do this and which R clause do I use?

It isn't possible for the Client to use Option A of the ECC without specifying and describing the works in their entirety, it isn't intended to be used as a call-off contract and would need significant amendment to make it work in the way you describe.

It would be better to use either the TSC (term service contract) or TSSC (term service short contract).