The e.m.f. of the following three galvanic cells:

I. Zn | Zn²⁺ (1 M) || Cu⁺² (1 M) | Cu

II. Zn | Zn²⁺ (0.1 M) || Cu²⁺ (1 M) | Cu

III. Zn | Zn²⁺ (1 M) || Cu²⁺ (0.1 M) | Cu

are represented by E₁, E₂ and E₃. Which of the following statement is true?