Assertion (A) : The quantization effect of charge can only be observed at microscopic level.
Reason (R) : The step-size of the electric charge is 1.6 x 10-19 C.
Answer & explanation
Correct answer: option 1
quantization of charge is meaningful only at microscopic level because the charges involved are of very small magnitude(of the order of $10^{-19}C$)
$\text{All charge is an integral multiple of e } = 1.6 \times 10^{-19} C.$
$ q = \pm ne$