Through Studies of Insect Malpighian Tubules,researchers Found That K⁺ Accumulated

Through studies of insect Malpighian tubules,researchers found that K⁺ accumulated on the inner face of the tubule,against its concentration gradient.What can you infer about the mechanism of transport?

A) Potassium transport is a passive process.
B) Movement of potassium into the lumen of the Malpighian tubules is an energy-requiring process.
C) Potassium moves out of the tubules at a faster rate than it moves into the lumen of the tubules.
D) Sodium ions will follow potassium ions.
E) Potassium moves into the tubules at a faster rate than it moves out of the lumen of the tubules.