Final answer:
Rinsing the glass stirring rod with DI water when you take it out of the flask is done to prevent contamination.
Step-by-step explanation:
Rinsing the glass stirring rod with DI water when you take it out of the flask is done to b. To prevent contamination. This is because any residual solution on the rod can contaminate other solutions or affect the accuracy of subsequent experiments. By rinsing with DI water, any remaining solution is removed, ensuring that the rod is clean and ready for further use.