B. Angle 1 and 2
Adjacent literally means next to, so just think which angles are next to eachother or share a leg
Im not an expert or anything, but i think for the innequality, i would say

as far as the amount of people she can invite, do 500-100=400 because of the setup fee, then, to find how many people she can invite. 400÷6.50 which leaves you with the highest amount of people she can invite without going over budget, as 61.