You can come with us, or you can stay at your uncle's house.
The first letter of the sentence must be capitalized so the third sentence is wrong.
In the first sentence, "your uncles house" is wrong. It should be "your uncle's house", meaning the "the house which beongs to your uncle".
And "Uncles'" is wrong because it shoud not start with an uppercase "U" because it is not in the beginning of the sentence and "uncles" is not a proper noun.
B. A teacher travels each year to visit family in South Africa. I mean, honestly, who cares? That's nice of her, but it won't really get the point across if Greg wants people to not only hear his speech but live it as well.
I hope this helps :)
A because you want to check the essay as a whole and each body of paragraph.
Hope this helped!