What does it mean if an organization$$s human capital return on investment is $$3?$

Question $12$ options:

a$)$

For every dollar an organization invests in human capital, the employees will generate $$3$ in return.

b$)$

For every dollar an organization invests in human capital, the employees will generate $$3$ in revenue.

c$)$

For every dollar an organization invests in human capital, the employees will generate $$3$ in capital assets.

d$)$

For every dollar an organization invests in human capital, the employees will generate $$3$ in productivity.