Final answer:
The noninverting buffer is used to increase drive current for a signal without changing its logical state. It is not primarily used for logical processing but to ensure signal integrity across a digital circuit.
Step-by-step explanation:
The noninverting buffer serves no logical purpose but is used to supply greater drive current at its output. The correct answer is c) Buffer. A buffer, in the context of digital electronics, is a logic gate that provides the same logical level at its output as its input, hence it does not change the data. Although it might seem redundant because it does not perform a logical function like transforming an input, its main purpose is to strengthen the signal so that it can drive more inputs or travel longer distances without degradation. For example, in a digital circuit, a buffer can be used to increase the driving capability to avoid signal loss or to isolate different parts of a circuit.