Which method is used for training on the job?

The correct choice emphasizes the Just-In-Time (JIT) process, which is particularly effective for on-the-job training. This method ensures that employees receive training right when they need it, just before they are required to perform a task. This approach is advantageous as it integrates learning with actual job duties, allowing for immediate application of skills and knowledge.

By following the JIT process, trainers can provide relevant information and skills in real-time, thus enhancing retention and increasing the likelihood of employees effectively applying what they've learned. This method also allows flexibility, enabling trainers to respond to specific needs as they arise during the work process.

In contrast, the other options lack the structured and supportive training environment necessary for effective on-the-job learning. Engaging in individual study without oversight does not provide immediate feedback or support, which can hinder skill development. Immediate hands-on training without guidance may lead to mistakes or misunderstandings, as employees might be unsure about the correct procedures. Relying solely on online modules does not account for the practical application of skills in a real work setting, which is crucial for comprehensive learning.