Type-B ARRs primarily act as:
That points to B: Transcription factors. Compared with the other options, Transcription factors is the one that correctly describes the Cytokinin concept. The wrong ones are A) Negative regulators; C) Receptors; D) Enzymes. If you’re stuck, eliminate anything that contradicts a basic fact you already know for this topic.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.