I never answer Unknown numbers and I quickly look them up to see where the call may be from and the comments on here are pretty accurate. I called back private and it sounds busy. Just block it.
Got call at 09:19 US-PDT (UST -07:00) and answered phone. Female voice telling me that she represents some unheard of organization for Breast Cancer and wants to know if they can count on us to donate if they send an envelope. I told her that it sounded more like they were "phishing" for credit card information and then I ended the call.