Which is the idependent variable in the following situation?:

A marine biologist wants to track the miles that a particular dolphin travels over the course of a year. The tracking system records the distance each week.
A. length of dolphin. B. number of dolphins C. weeks of tracking. D.miles traveled

In this scenario, the independent variable is the factor that the researcher purposefully manipulates or controls. It would be the weeks of tracking (C). The researcher is tracking the miles traveled by the dolphin over the course of a year, but they are controlling or deciding how many weeks they will monitor the dolphin's movements. They could choose to track it for a shorter or longer period of time, which would affect the amount of data collected. Therefore, the weeks of tracking is the independent variable.