I am annoyed everyday. Unknown people are adding me to their circles. How to allow only the people in my 'Extended Circles' to add me to their circles?
You can't stop people from adding you. If you don't post public you have nothing to worry about, they will never see a thing. If you post public even people who have not added you to their circle will see the post if they visit your profile. Even people who have not joined Google+ will see it. Public really means anyone. So either way you have nothing to worry about people adding you to their circles. It makes no difference at all.
just go to the option of HAVE YOU IN CIRCLES and just select action button in wright side and in action click select all and again press action button click block.Everyone will be blocked even some oof your frns might be blocked then click action buttton and in that click view blocked then you'll get blocked list if it contains your frns u can unblock them and add them in your circles.