Step 1: In a 'coming together' federation, independent States come together on their own to form a bigger unit, so that by pooling sovereignty and retaining identity they can increase their security. Step 2: The USA, Switzerland and Australia are examples of this first category; in such federations all the constituent States usually have equal powers and are strong vis-a-vis the federal government. Step 3: In a 'holding together' federation a large country divides its power between the constituent States and the national government - India, Spain and Belgium belong to this category, where the central government tends to be more powerful. Step 4: England (UK) is a unitary state. Hence the best example of a coming together federation among the options is Switzerland - Option (D).