Google+: a. has a built-in targeting mechanism with its circles. b. allowed hashtag searches until november 2015, then eliminated that option. c. added a feature called "companions" for search purposes. d. all of the above. e. only a and b are correct.

e) only A and B are correct

Explanation: Google + is a service that is used for social networking. It is like the other social networking devices work and provides similar services like searching, connecting people etc. This service was not successful approach among the users.Thus it was shut down at the certain point of time.

It had the mechanism in which the circles was used got the targeting and used for connecting account with other Google services.It also had the feature introduced named hashtag searches for searching but then discontinued this feature.So, only statement(a) and (b)are correct.Thus option(e) is the correct option.