A mixed economy is one that incorporates elements of both capitalism (private enterprise) and socialism (government intervention). While it's difficult to pinpoint an exact number of nations classified strictly as mixed economies due to the varying degrees of mixed economic systems, it is generally understood that a significant majority of the world's countries can be classified in this category.
In the context of your options, while specific numbers might be debatable, the most fitting answer to indicate a large number of nations with mixed economies would be 70. Most countries in the world have aspects of both market and planned economic systems.
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