$$\text{HClO}_4$$ is used in etching of liquid crystal displays whereas $$\text{H}_2\text{C}_2\text{O}_4$$ is present in vegetables like spinach which causes itching to throat. Consider the following statements for these compounds. 

(i) is that $$\text{HClO}_4$$ is a stronger acid than $$\text{H}_2\text{C}_2\text{O}_4$$. 

(ii) is that $$\text{HClO}_4$$ is a weaker acid than $$\text{H}_2\text{C}_2\text{O}_4$$. 

(iii) is that $$\text{H}_2\text{C}_2\text{O}_4$$ is a reducing agent and $$\text{HClO}_4$$ is an oxidizing agent. 

(iv) is that the conjugate base of $$\text{HClO}_4$$ is stronger than the conjugate base of $$\text{H}_2\text{C}_2\text{O}_4$$. 

The correct statements are