Which statement best describes the constant of variation for the relationship?
1) The constant of variation shows that it takes 84 full-day shifts to complete one project.
2) The constant of variation shows that each worker needs 21 days to complete a project.
3) The constant of variation shows that it takes 21 full-day shifts to complete one project.
4) The constant of variation shows that 84 workers are needed to complete a project.