The correct option is B prone
Option B: 'Prone' means 'likely to suffer from'. It is relevant to the given sentence in meaning, as mentioned in the line "with an average of twenty accidents per year". This means that the 'area' is prone to accidents, i.e., accidents are likely to happen in this area. Hence option B is correct.
Option A: 'Proven' means 'to have demonstrated the truth of'. An area cannot be proven as 'accident'. The meaning formed is ambiguous.
Option C: 'Prevention' refers to the action of stopping something from happening. The word does not complete the sentence in meaning.
Option D: 'Driven' means 'operated, controlled by'. The meaning thus formed is vague. An area cannot be operated or controlled by accidents.
Hence options A, C and D are incorrect.