Answer:
These two statements are correct:
A. Potential employers may have believed that those with black-sounding names had completed less education.
African Americans on average have less rates of graduation from tertirary education than White Americans.
This situation might lead some employers to develop streotypes about African Americans being less educated, when it is clearly an error, and unfair, to reject a potential employee because of stereotyping instead of making an individualized analysis of his or her abilities.
D. Hiring firms may have believed that those with black-sounding names were more likely to have a criminal conviction.
African Americans on average are incarcerated more often than other ethnic groups in the US. The reasons for this are complex but poverty and racial discrimination are two big factors. This situation causes some employees to develop streotypes, leading to unfair situations as described in the first answer.