The least possible Venn diagram for the given statements is as follows,
Conclusions: I. All Alpha being Gamma is a possibility → True (All Alpha being Gamma is a possibility as shown in the diagram below.)
II. No Beta are Delta → False (No Beta being delta is a possibility but it's not definite as no direct relation is given between Beta and Delta.) III. Some Beta are not Delta → True (Beta which are Gamma can never be Delta as shown in the least possible diagram.) Hence, All except II follows is the correct answer.