The most important characteristic of a good detective is if they are observational or not, they won't every solve any case if they don't keep their eyes wide open, and observe.
The one of the left with all the colored rings :•)
The linking verb is 'because'
Answer: A. Outer ugliness is not an indicator of inner ugliness
Explanation: This is the answer because B. is a fact, C. is also a fact, and D. is just a quote.