Correct Answer: A

Rationale: The correct answer is A. It is credible if published in a peer-reviewed scholarly journal because peer review ensures that the research has been evaluated by experts in the field for quality and accuracy before publication. This process enhances the credibility of the research source. Choice B is incorrect because not all online sources are unreliable; credibility depends on various factors beyond the publication medium. Choice C is incorrect because author affiliations can indeed impact credibility, but they are not the sole determinant. Choice D is incorrect as the frequency of citations can indicate the impact of a source but does not guarantee its credibility.

Correct Answer: C

Rationale: The central idea of the passage is that there are many different kinds of self-improvement classes available. The passage discusses various topics such as cooking, yoga, language learning, and computer skills, emphasizing the range of options for self-improvement classes. This choice captures the main theme of the passage focusing on the diversity of available classes for personal development.

Correct Answer: C

Rationale: The correct answer is C, compromise of the immune system. The passage states that alcohol abuse can weaken the immune system, making individuals more susceptible to infections and illnesses. This compromise of the immune system can lead to various health issues and exacerbate existing conditions. Choices A, B, and D are incorrect based on the passage. While the passage discusses the impact of alcohol abuse on magnesium absorption and kidney function, it does not directly attribute these issues to alcohol abuse. Gastrointestinal disorders are mentioned in relation to magnesium absorption but are not specifically linked to alcohol abuse.

Correct Answer: A

Rationale: If you are among the people for whom a flu vaccine is recommended, the best course of action is to call your doctor for an appointment and get the vaccine. Getting vaccinated can help protect you from getting the flu and reduce the spread of the virus to others. It is important to prioritize your health and take preventive measures, especially during the flu season.

Correct Answer: A

Rationale: The correct answer is A, 'The New York Times.' The article is an excerpt from The New York Times, which is a renowned newspaper known for publishing articles on various topics. The other options, Edwin M. Stanton, Frederick Seward, and Major Rathburn, are specific individuals mentioned within the article but are not the authors of the article. Edwin M. Stanton is identified as the Secretary of War, Frederick Seward is mentioned as one of the individuals harmed during the assassination, and Major Rathburn is present in the scene described in the article. Therefore, the most likely author of this article is The New York Times, a reputable source for news coverage.