The phenomenon of photoperiodism was first reported by:
Correct option is B, Garner and Allard. In PHOTOPERIODISM problems like this, the accurate statement is Garner and Allard; the others are common mix-ups. Not these: A) Darwin; C) Bünning; D) Went. Tissue transport questions usually turn on xylem vs phloem, living vs dead cells, or source vs sink.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.