Well, let's see whether there are any mistakes in the sentences:
A. Who is Marys teacher this year? 
here we're missing an apostrophe,the correct sentence would be:
A. Who is Mary's teacher this year? 
B. Last summer, we visited California.
-this is the correct answer!
 C. My doctors name is Dr Habeeb.
Again, a missing apostrophe! it should be:
My doctor's name is Dr Habeeb.
 D. Jennifer bought cupcakes diet soda and potato chips at the store. 
Here we are missing a comma, like this:
Jennifer bought cupcakes, diet soda and potato chips at the store.