Potassium ion influx theory of stomatal movement was proposed as an advance theory by:
Pick C: Imamura. Thinking through STOMATA MOVEMENT step by step rules out the lookalikes and leaves Imamura. Skip these: A) Lloyd; B) Levitt; D) Fischer. For hormones and genes, match the molecule or gene to its real role, not a neighboring pathway.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.