A Healthy Individual,weighing 60 Kg,receives an Infusion of 1 L

A healthy individual,weighing 60 kg,receives an infusion of 1 L of isotonic saline to which 20 mEq of K⁺ has been added.After the infusion,the plasma [K⁺] of this individual has increased from 3.5 mEq/L to 7.8 mEq/L.What is the most plausible explanation for the development of hyperkalemia in this individual?

A) K⁺ shifts from the intracellular fluid (ICF) into the extracellular fluid (ECF) .
B) Renal excretion of K⁺ is impaired.
C) The increase in plasma [K⁺] of 4.3 mEq/L is what is expected from the addition of 20 mEq/L of K⁺ to the ECF.
D) The ECF volume contracts.
E) Hyperosmolality develops.