No they can't. They still have to have a search warrant, or they cannot legally use your phone against you in the court of law.
Some countries are developed and some are still developing
Im 99% sure the answer is B. :)
I wont write you a 4 paragraph essay, but what I will do is give you some advice. When you're writing an essay, the paragraphs don't have to be massive. You can use 4 sentences, and it will be considered a paragraph. Add the basic information it wants, and no more. Good luck!