Concept:Public relations is about building and keeping a favourable public image for an organization and its products.Explanation:The phrase "deliberate and sustained efforts" shows a planned, long-term activity, not a one-time action.The goal is "creation of goodwill" — gaining trust and a positive reputation from the public.Public relations directly achieves this by managing communication and relationships with the public.Advertising and sales promotion are usually short-term or paid tactics.Rebranding only changes the organization's look or identity and does not guarantee sustained goodwill.Answer:A. public relations.