What are a.b.c. on Peter Drucker's 'Theory of the Business?

" The assumptions on which the organization has been built and is being run no longer fit reality. These are the assumptions that shape any organization’s behavior, dictate its decisions about what to do and what not to do, and define what the organization considers meaningful results. These assumptions are about markets. They are about identifying customers and competitors, their values and behavior. They are about technology and its dynamics, about a company’s strengths and weaknesses. These assumptions are about what a company gets paid for. They are what I call a company’s theory of the business."