Considering ONLY these SLC models: Waterfall, V-Shaped, Spiral, Evolutionary Rapid Prototyping, RAD, and Incremental; select the most suitable lifecycle models for the scenarios below (provide your reasoning for each one):

a. Developing an updated version of a factory operating system. The project includes the addition of 24 new functions, bug fixes, and enhanced UI. It is required to have at least 14 of the new functions to ready for operation within 2 to 3 months, while the rest of the functions can be added in the next 4 months through one or two updates. Budget is reserved for the project up front and there is a chance for good bonus if the whole project was delivered within 3 months. You are responsible for hiring the staff and determine their level of experience.

b. A new technology has been recently introduced for wireless transmissions. An electronic company (medium-sized) wants to design a new product that uses this technology and be the first one to do so. The company has previous experience in wireless communications, but this is the first time it tries a extremely new technology. Engineering teams will be assembled from the current staff, with a possibility of hiring up to 4 field-specific specialists. Training/education on the new technology will be provided by the designer of the new technology for 10 days. The company wants to show either a working product (with basic functionality) or a proof-of-concept prototype in an upcoming conference four months from now.

c. A company wants to creates a modern version of its current sales system. No new functions are required except for allowing the addition of different discount schemes in the future. You, as the supplier, are required to provide one or two prototypes during your development of the software. However, it is all up to when the client company hires an experienced evaluator. The emphasis is on verifying the current functions of the software are successfully transferred to the new software.

d. A software project where the client demands his continuous involvement in the project, as they have some experience and want to add to it for future collaborations.