The unit of Ecell is

The correct option is V (Volt).

The electromotive force (emf) of a galvanic cell, commonly denoted as $E_{\text{cell}}$, represents the difference in electrical potential between the two electrodes of the cell.
Since potential difference is defined as the work done per unit charge, its standard unit of measurement is the Volt ($\text{V}$).
One Volt is equivalent to one Joule per Coulomb:

$1\text{ V}=1\text{ J}{\text{ C}}^{-1}$

Therefore, the standard unit of $E_{\text{cell}}$ is Volt (V).