$\underline{ \mathrm{A} }$ performed an elegant experiment with an $\underline{ \mathrm{B} }$ plant to show that in bright sunlight, small bubbles were formed around the $\underline{ \mathrm{C} }$ parts, while in dark they did not.

Study the following lists and match the discoveries and/or inventions made by the scientists during ${20}^{\text{th }}$ century

The correct answer is

Radioactive isotopes employed to study photosynthesis are