Identify, which of the following forms of energy can become only positive

option (a) : K.E

Upon evaluating $K.E=\frac{1}{2}m{v}^2$

$m,v^2$ are always positive

So K.E. will remain always positive

It is correctly meeting the requirement.

Option (b) : P.E

We know potential energy = work done against conservative forces.

We take force of attraction as $-ve$

And force of repulsion as $+ve$

So it can become some times $+ve$ and some times $-ve$.

It is not supporting the requirement.

Option (c) : Mechanical energy

We know mechanical energy = K.E + P.E

K.E is always positive

But P.E may be negative.

So mechanical energy can become negative.

It is not correctly meeting the requirement.

Option (d) : We are certain about K.E, but not M.E can always become positive.

So it is also not supporting the requirement.