The correct option is C Blackman
Law of limiting factors was given by Frederick Blackman. The law states that “If a chemical process is affected by more than one factor, then its rate will be determined by the factor which is nearest to its minimal value: it is the factor which directly affects the process if its quantity is changed”.
Joseph Priestley confirmed that air is essential for photosynthesis and growth of plants.
Robin Hill discovered that green particles obtained from broken cells could produce oxygen from water in the presence of light and a chemical compound such as ferric oxalate is able to serve as an electron acceptor. This reaction is known as the Hill reaction.
Justus von Liebig identified that nitrogen, phosphorus and potassium are essential for plant growth.