The correct answer is: Training

Rationale: Conditioning may have sounded familiar if you only read as far as 'modification of behaviour', but it involves specific repetition-and-reward techniques. Education is the gradual acquisition of knowledge, by learning and instruction, often leading to qualifications. Development is a wider experience of the growth or realisation of a person's ability and potential through a wide range of learning experiences.

Pitfalls: This kind of related terminology lends itself to exam questions. Training, education and development all involve 'learning', but the learning experiences are of different types, and with different overall aims.