Why will a reaction occur between calcium oxalate and platinum?

Complex formation

Explanation:

At first sight, one may think that a reaction between calcium oxalate and platinum metal is impossible considering the relative positions of the two metals in the electrochemical series.

However, in solution, calcium oxalate dissociates into calcium and oxalate ions. When platinum is added to this solution, a complex is formed between the platinum ions and the oxalate ions. Hence a reaction occurs for this reason.

i'm assuming that the correct answer is indeed the first one/ "a"..

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.