The following solution is based on the assumption, that O is the center of the circle. I am not sure if that is save to assume, but I am not sure how to solve the question without that.

Since the points E and D are on the circle, the lines OE and OD are radii of the circle and the angles OEA and ODA must be 90°. Since OEAD is a quadrilateral, the sum of all four angles must be 360°, so the remaining angle EOD must be 120°. Answer A.

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\(\sqrt{-1}\) \(2^3\) \(\Sigma\) \(\pi\) ... and it was delicious!

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