Task: Question Answering
Input (English): Question: A columbimétrica valuation: 
 Options:  <1> It is always done at controlled potential. <2> Always use a platinum macroelectrode. <3> It does not need a system indicating the end point. <4> You need the current to be controlled. <5> You always need the titrant to be added from a burette.
Output (English): 4