The following question is a real toeic question.

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We should find an effective ______ of bringing the union and management together for our future.

a) instrument b) means c) technique d) approach

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I know that " an effective means of ~~" is a right answer.
But how about "instrument"?

Is it impossible to use "instrument" in the sentence above?


Please refer to the following.

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instrument :
someone or something that can be used in order to make something happen:
The government has a number of policy instruments it can use for this purpose.
instrument of: an important instrument of quality control

Macmillan Publishers Ltd. 2002

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Please help me.