In 2019, who was sworn in as the Attorney General of the United States under the administration of President Donald Trump?

Introduction / Context:
The Attorney General of the United States is the head of the Department of Justice and serves as the chief law enforcement officer of the federal government. The person who holds this office plays an important role in legal policy, federal prosecutions, and advising the executive branch on legal matters. Examinations in general knowledge sometimes ask about the names of key office holders during particular administrations. This question focuses on who became Attorney General in 2019 under President Donald Trump.

Given Data / Assumptions:

• The time frame is 2019, during the presidency of Donald Trump.
• Options include Dick Thornburg, William Barr, Edwin Meese, and Janet Reno.
• All of the names listed have served as Attorneys General at different times in United States history.
• The task is to choose the person whose appointment matches the specified year and administration.

Concept / Approach:
William Barr served as Attorney General of the United States twice in his career. His first term was under President George H. W. Bush in the early 1990s. Later, he was nominated again by President Donald Trump and was sworn in as Attorney General in 2019. Dick Thornburg served as Attorney General before Barr in the late 1980s and early 1990s. Edwin Meese held the position in the 1980s during the Ronald Reagan administration. Janet Reno served as Attorney General during the presidency of Bill Clinton in the 1990s. Therefore, only William Barr matches the combination of being sworn in as Attorney General in 2019 under President Donald Trump.

Step-by-Step Solution:
Step 1: Focus on the year 2019 and the administration of President Donald Trump. Step 2: Recall which candidate among the options was nominated by President Trump. Step 3: Remember that William Barr returned to the role of Attorney General in 2019 after first serving in the early 1990s. Step 4: Identify the time periods when Dick Thornburg, Edwin Meese, and Janet Reno held the office, noting that none match 2019. Step 5: Select William Barr as the correct answer.

Verification / Alternative check:
Verification can be done by recalling major news coverage from early 2019 regarding Senate confirmation hearings for the new Attorney General under President Trump. Those reports referred to William Barr as a former Attorney General returning to the office. Historical lists of Attorneys General show Dick Thornburg before Barr during the administration of George H. W. Bush, Edwin Meese during Ronald Reagan's term, and Janet Reno under Bill Clinton. None of these correspond to the year 2019, confirming William Barr as the accurate choice.

Why Other Options Are Wrong:
Dick Thornburg served as Attorney General from the late 1980s into the early 1990s and was not associated with the Trump administration. Edwin Meese was Attorney General during the mid 1980s under President Ronald Reagan, long before 2019. Janet Reno was Attorney General during the 1990s in the administration of President Bill Clinton. Since these individuals served in earlier decades and with different presidents, they do not fit the specific requirement of being sworn in as Attorney General in 2019 under President Donald Trump.

Common Pitfalls:
Students may see familiar names and choose incorrectly without paying close attention to the time period and presidency mentioned in the question. Another common mistake is to assume that the most famous or longest serving Attorney General on the list must be the answer, rather than matching names to exact years. Carefully linking the office holder to both the president and the date avoids such errors.

Final Answer:
The person who was sworn in as Attorney General of the United States in 2019 under President Donald Trump is William Barr.