Leaf longevity increases in which mutants?
B fits best: Ethylene insensitive. Keep the Phytohormone ALL basics straight and Ethylene insensitive stands out as the precise answer. Avoid: A) Auxin insensitive; C) GA deficient; D) ABA insensitive. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.