Final answer:
The potential side effect of having the spleen removed is an increased risk of blood clot formation.
Step-by-step explanation:
The potential side effect of having the spleen removed is an increased risk of blood clot formation (option C). The spleen plays a role in filtering the blood and removing platelets that are no longer functioning effectively. Without the spleen, platelets may build up in the blood and increase the risk of clot formation.