Final answer:
A Staff Sergeant (SSgt) in the Air Force may achieve the 7-skill level. For non-English fluent Army recruits, the designed test was the Army Beta.
Step-by-step explanation:
An Airman can achieve the 7-skill level at the rank of Staff Sergeant (SSgt), which is option d. Achieving the 7-skill level indicates that the Airman has obtained a high level of technical proficiency within their career field and is often associated with increased leadership roles and responsibilities. This is a part of the professional development within the United States Air Force.
As for the test designed for Army recruits who were not fluent in English, the correct answer is c. Army Beta. The Army Alpha test was designed for literate recruits, while the Army Beta test was developed during World War I for those who were illiterate or not proficient in English.