The correct option is
D Blunder
The given word 'error' means 'a deviation from accuracy or correctness'.From the options, Option D: 'misfortune' best expresses the meaning of the given word. Hence option D is correct.
Option A: 'A 'misadventure' is an 'instance of bad fortune or mishap'.
Option B: 'Misgivings' is a feeling of doubt or mistrust
Option C: 'Ambiguity' means 'a doubtfulness or uncertainty of meaning or intention.
These words do not mean the same as the given word, hence options A, B and C are incorrect.