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ABC, Reason：the number of ways to …without replacement basically means the number we choose is a product of three consecutive numbers , thus 24=2x3x4; 60=3x4x5; 120=4x5x6; etc etc. not sure how to solve this by using combinatorics.

Edit: no A cuz the least value of n is 5 (5C3=10）

only BC

no, 6C3 is 20; 5C3 is 10. Therefore, n= 5 and 6. Then solutions are 60 (5x4x3) and 120 (6x5x4)

ahh yes! my mistake Thanks for correction