Strigolactones promote symbiosis with:
That points to C: Arbuscular mycorrhizal fungi. Compared with the other options, Arbuscular mycorrhizal fungi is the one that correctly describes the Striglactone concept. The wrong ones are A) Rhizobium only; B) Ectomycorrhiza; D) Lichens. 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.