Which of the Following Statements Is/are Correct?
A)The Value Of \varepsilon

Which of the following statements is/are correct?

A) The value of $\varepsilon$ ° is equal to zero in a concentration cell,and the value of $\varepsilon$ is equal to zero in any cell at equilibrium.
B) The value of $\varepsilon$ ° can be equal to zero in a concentration cell,and the value of $\varepsilon$ must be equal to zero in a concentration cell.
C) The values of $\varepsilon$ ° and $\varepsilon$ are equal to zero in any cell at equilibrium.
D) ( $\varepsilon$ °) can never be equal to zero.
E) At least two of the above choice (A-D) are correct.