What is the full form of 'Qubit'?

The full form of 'Qubit' is 'Quantum bit'. A qubit is a fundamental unit of quantum information. It represents the basic unit of data in quantum computing, similar to a classical bit in classical computing. Unlike classical bits that can only exist in a state of 0 or 1, qubits can exist in a superposition of both 0 and 1 simultaneously, thanks to the principles of quantum mechanics. This property allows qubits to perform complex calculations and solve certain problems much faster than classical computers. Hence, the correct answer is 'Quantum bit' because it correctly describes the nature of a qubit in the context of quantum computing.