Which choice completes the text so that it conforms to the convention…

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Integrating insights from economics and psychology, researchers in the field of behavioral economics explore a variety of topics. Lucía Macchia of the University of Oxford studies socioeconomic other researchers investigate areas such as organizational behavior and personal finance.

Which choice completes the text so that it conforms to the conventions of Standard English?

inequality, for instance;

inequality; for instance,

inequality, for instance,

inequality for instance;