On-the-job training is provided by________.

The correct option is D The line supervisor on the shop floor itself
On-the-job training is mostly provided for unskilled and semi-skilled works. In this the employees are trained while doing the work, no separate training programs are organized for the employees.

This training is provided by the supervisor who is superior to the workers. They train the workers about the workspace and the task to be performed and keep an eye on their progress.

Hence, option (A) is the correct answer.