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For categories 1 and 2, you can get away with both very long (i.e. Maxi Dresses) and shorter than normal (mini or in the case of casual micro mini).
For category 3, knee length through calf length is your best bet.
For categories 4 slightly above knee length through calf length will suit the occasion well.
For category 5 Ankle to Floor length is best.
For category 6 a couple of inches above the knee to knee length is the most common.
For category 7 your options are more open, but for your red dress to fit in the with occasion a somewhat flair mico mini to knee length will give you room for dancing, and hopefully a sense of flirty fun that will help you enjoy the occasion.