Task: Question Answering
Input (English): Question: Comparing the redox behavior of the silver and sodium systems: 
 Options:  <1> Na + is a good oxidant, because its system has a high reduction potential. <2> Ag is an excellent oxidant, so it does not rust in the air. <3> Ag + is a good oxidant, and therefore easily reducible to metal. <4> The two metals dissolve in acid medium releasing H2 <5> The two metals dismute spontaneously in water.
Output (English): 3