Choose the taboo letters of license plate number

the first letter is "s". The main reason why this letter is taboo is that the homonym is too ugly and homophonic with the word "death". After all, many car owners in China are still very taboo about the word "death".

the second letter is "b", which is homophonic with the national curse, especially when combined with "s", "2" and "t".

The third letter is "M", which is not as taboo as S and B. The homonym of M and S is stupid or abusive, and the homonym of M and B is also ugly. Besides, m also means buying and selling.