Active BIN2 phosphorylates which transcription factors?
That points to B: BES1/BZR1. Compared with the other options, BES1/BZR1 is the one that correctly describes the Brassinosteriod concept. The wrong ones are A) ARF; C) DELLA; D) HY5. 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.