The answer is:
C. What type of dog food has the best nutrition for dogs.
This is because, unless instructed, dog walkers will generally not feed the dogs they walk, thus they shouldn't give information about it to you; it's not reliable information.
"Contrast" means to be different, or to differ. The answer is D. However, because "however" is used when you start to talk about something different.
I hope this helps! :D
answer
c. he enjoyed sharing his life story
