Intellectual property rights and the opportunity to profit from their ideas gives creators
a. a guarantee they will be successful
b. government tax credits for twenty years
c. an incentive to bring their ideas to market
d. an opportunity work without any risk

I think that the best answer is "c. an incentive to bring their ideas to market" - you can see that through the statement of "the opportunity to profit from their ideas"- an opportunity to profit is an incentive to work and in the case of the creators - to bring their ideas to market.

However, an opportunity to profit is not a guarantee that one will profit - so for example option a) is wrong. 

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