Sposable — Make a recommendation you can defend
https://sposable.com/labs/evidence-to-recommendation/

Alder: 2 × 80 = 160 euros; 24 seats meets capacity; step-free access confirmed; whiteboard included (A).
Birch: 2 × 65 = 130 euros; 20 seats meets capacity; access unknown; whiteboard included (B).
Cedar: 2 × 70 = 140 euros; 16 seats fails the 18-person requirement; access confirmed; no whiteboard (C).

Recommendation: Alder is the best-supported provisional choice because it meets the stated room-hire budget, capacity and access requirements and includes a whiteboard. Before booking, confirm availability and any additional charges. Birch costs 30 euros less for room hire and could become preferable if step-free access and total costs are confirmed. Cedar does not fit 18 people on the supplied facts.

Why it works: an unknown is not turned into a fact, and the recommendation states what could change it.