This number keeps calling. More than once, every day. One site said it is March of Dimes, but I do not know how to verify that. It is not identified on the caller ID as such. ID only says Sterling, VA

Doesn't matter.  This is just one of a multitude of charity calls that are designed to enrich the pockets of the call center owners and give nothing to the charity.  Never donate over the phone.  If you want to donate, give directly to the charity.