Mousoomee was asked to compare the reactivity of metals Zn and Fe. She took zinc granules and ferrous sulphate crystals in a 50 mL beaker. She waited for 10 minutes but no reaction took place. The reason was:

(a) the beaker was small.

(b) she should have used a clean and dry test tube.

(c) the ferrous sulphate was not as aqueous solution.

(d) the zinc granules were big in size.