Which type of work distribution between development and testing is suited for each of the following cases?

a) A product that is using emerging technologies that require niche skill set.

b) A product that is going through very short release cycles with frequent builds and a product where in multiple releases are going on at the same time.

c) A product to which incremental features are being added on the top of already existing features that are stable.

d) A product being developed in an organization where there are clear cut processes and methods of hand over of work from development.