Final answer:
d. Calcium
Excessive intake of calcium can lead to constipation, making it the likely mineral causing this problem.
Step-by-step explanation:
The mineral that is likely to be the possible cause of constipation when taken in excess is calcium. When calcium intake is high, it can lead to constipation due to its role in muscle contraction and its tendency, in excess, to bind with other waste products in the digestive system, making stools harder to pass. Whilst magnesium often has a laxative effect and can be used to treat constipation, and phosphorus and potassium imbalances typically do not cause constipation, excessive calcium can lead to this undesired effect.