Need help with a Home Inspector's test please?

Question:I am taking a test for Home Inspection and am having a hard time finding some of the answers to the questions...

my email address is fallenangelmom@yahoo.com if anyone wants to offer more help, or a website, I would appreciate it.

So here goes:
Where is the best place to put a thermostat? a. above heating registers b. near exterior door c. wall of dining room d. in direct sunlight... my process of elimination says C, but ?

Next: For fire safety, there should be no heating/cooling returns in: a. garages b. bedrooms c. dining rooms d. ceilings... ?

Next: Which of the following is the worst case scenario: the top of the foundation wall is: a. at grade b. 3 inches below grade c. 16 inches above grade d. 10 inches wide... ?

If anyone can even give me a website to research, I'm able to do that, but I can't seem to find one that has the information that I need...

Thanks so much,
Melanie

Answers:
answers are C A B