Please help!!!

A family named Schneider changed its name to Snyder during World War I. David
Greenstein became David Green when he opened his first store. Joseph Stanislowski
become Joseph Stanley when he began looking for a job.

Why did these people change their names?

A. to avoid prejudice because of their ethnic backgrounds

B. to have the name of famous Americans

c. to show pride in their ethnic backgrounds

d. to meet the immigration lows which require each person to have an American name