Task: Question Answering
Input (English): Question: Regal water dissolves gold because of its two components: 
 Options:  <1> Sulfuric acid acts as an oxidant and hydrochloric acid forms a soluble chlorinated complex of Au3 +. <2> Hydrochloric acid increases the oxidizing power of nitric acid. <3> Nitric acid acts as an oxidant and hydrochloric acid forms a soluble chlorine complex of Au3 +. <4> Hydrochloric acid acts as an oxidant and nitric acid forms a soluble complex of Au3 +. <5> Nitric acid acts as an oxidant and hydrochloric acid forms a soluble chlorinated complex of Au2 +.
Output (English): 3