Concept:For n distinct items, total subsets are 2n. Choosing at least one item gives 2n−1 ways.Explanation:At least one red dye from 5 red dyes: 25−1=32−1=31 ways.At least one black dye from 4 black dyes: 24−1=16−1=15 ways.Brown dyes have no restriction, so any number can be chosen: 23=8 ways.The choices are independent, so multiply: 31×15×8.31×15=465.465×8=3720.Answer:3720, which is Option B.