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decide (up)on someone or something
to choose someone or something; to make a judgment about some aspect of someone or something. (Upon is formal and less commonly used than on.) Will you please hurry up and decide upon someone to vote for? I decided on chocolate.
decide onor decide upon
To choose something or someone after deliberation: We decided on green as the color for the nursery. I've decided upon the red shoes; you can put the black ones back.