Explanation:

The fundamental computer processing cycle, often referred to as the IPO cycle, consists of three main stages: 'Input' (receiving data), 'Processing' (manipulating and transforming data), and 'Output' (presenting the results). Option (a) 'Input, processing and output' correctly identifies these three essential steps. The other options describe broader concepts (b, d) or components and outcomes (c), but not the sequential operational cycle itself. Therefore, (a) is the most accurate description of the basic computer processing cycle.