In which paragraph does the writer mention a causal relationship that resulted in a decline in personal care habits?

The official answer key on page 6 (table 'ĐÁP ÁN') gives answer B for Question 8. The source document provides only the answer key and no written explanation. Note: the referenced reading passage about hygiene appears on an earlier page not included in the supplied images (page 2 shows a different passage, 'Stress', belonging to Questions 9–13), so the paragraph-level justification cannot be verified from the supplied pages; answer B is retained exactly as printed in the official key.