All of the following are unifying factors EXCEPT aCommon language bEthnic and racial diversity cnationalism deffective transportation and communication

The unifying factors among the options given are:

a) Common language - A common language allows people to communicate effectively, share ideas, and understand each other, which can bring them together.

c) Nationalism - This is a strong feeling of pride in and devotion to one's country. It can unify people by creating a sense of shared identity and common purpose.

d) Effective transportation and communication - These can bring people closer together by making it easier for them to interact and exchange ideas, even if they are physically far apart.

The option that is NOT a unifying factor is:

b) Ethnic and racial diversity - While diversity can enrich a society in many ways, it does not inherently unify people. In fact, it can sometimes lead to divisions if not managed properly. Therefore, ethnic and racial diversity is not a unifying factor in the same way as the other options.