Final answer:
The injected solution was isotonic.
Step-by-step explanation:
The correct answer is d. True, the solution was isotonic.
An isotonic solution is one that has the same concentration of solutes as the cells in the body. If the solution injected into the patient had caused the red blood cells to burst, it means that the solution had the same osmotic pressure as the cells, indicating that it was isotonic.
If the solution had been hypertonic, it would have had a higher concentration of solutes than the cells, causing water to move out of the cells, leading to cell shrinkage. If the solution had been hypotonic, it would have had a lower concentration of solutes than the cells, causing water to move into the cells, leading to cell swelling.