A Secondary Cell Is One Which ____; This Is Possible

A secondary cell is one which ____; this is possible because ____.

A) is driven by a primary cell; the cell reactions are coupled
B) is disposable without harming the environment; no mercury is used
C) is rechargeable; the cell reaction is reversible
D) has double the lifetime of a primary cell; two primary cells are placed in parallel
E) has double the voltage of a primary cell; two primary cells are placed in series