Which of the following is NOT a source of "Human capital"?

Investment in salary

Investment in education is considered as one of the main sources of human capital. There are several other sources as well which includes:

1. Investments in health: A healthy person can work better.
2. On- the job training: Increases the labor productivity.
3. Migration: People migrate to difference place in order to increase the earnings.
4. Information: Information is necessary to make decisions regarding investments in human capital.