The quantisation of electric charge is attributed to

The correct answer is Option (1) → R. A. Millikan

NCERT (2026-27):
Introduction – “… In 1913, the American physicist R. A. Millikan (1868-1953) performed the pioneering oil-drop experiment for the precise measurement of the charge on an electron. He found that the charge on an oil-droplet was always an integral multiple of an elementary charge, 1.602 × 10^–19 C. Millikan’s experiment established that electric charge is quantised.”