Which of the following geometric figures is possible to construct?

A pentagon's angles sum to $$540^\circ$$, so 4 right angles would force the fifth to be a degenerate $$180^\circ$$, which is impossible. A parallelogram only has two distinct angle values (equal pairs), so it can never have exactly 3 obtuse angles, and a hexagon with 4 proper reflex angles would already exceed its total angle sum of $$720^\circ$$. The octagon in option (b) has angles summing correctly to $$1080^\circ$$ and is a genuinely constructible equilateral star-like shape.