Step 1: Understanding the Concept:
Check for countability errors, preposition usage, and relative pronouns.
Step 2: Key Formula or Approach:
1. "Fewer" for countable, "Less" for uncountable.
2. "Since" for past start time in present perfect.
3. "Who" for people.
Step 3: Detailed Explanation:
A. "Cars" is countable $\rightarrow$ should be "fewer". (Incorrect)
B. Correct comparative. (Correct)
C. Should be "since Monday". (Incorrect)
D. Correct idiom. (Correct)
E. Preferred usage is "who" for persons. (Generally considered incorrect in formal tests)
F. "Media" is plural, "are divided" is correct for individual actions. (Correct)
Step 4: Final Answer:
Sentences B, D, F are correct.