I think it is probably a research/survey call.  I used to work for a research company and we called (via computer dialing) to ask questions on health, education, politics, etc.  NO selling!  Just getting opinions!  It was pretty interesting and with elections in the future, it is probably about politics.  These companies (who work for other companies) disseminate peoples answers, to learn what people are thinking or are looking for, in a candidate.!
When you answer and there is nothing on the other end, it is because someone answered before you!