When substance 'A' is added to a solution of 'B', a color change is observed. However, when 'C' is added to the solution of 'B', no color change occurs. What can be concluded about the relative reactivity of A, B, and C?

Select the option that correctly evaluates the two statements labeled Assertion (A) and Reason (R). Assertion (A): A copper wire placed in an iron sulphate solution shows no visible chemical reaction. Reason (R): Copper is less reactive than iron in the reactivity series.

Which of the following chemical reactions is least likely to occur spontaneously under normal conditions?