Which of the following cannot be recharged ?
A primary cell
Explanation of correct option:
(a) A primary cell: A primary cell cannot be charged again it has to be discarded after use.
Explanation of incorrect option:
(b) Secondary cell: A secondary cell can be recharged again after use.
(c) Mobile battery: A mobile battery is rechargeable.
(d) All of these: Option (a) is rechargeable, whereas option (b) and (c) are non-rechargeable.
Thus, the correct option is (a).