Last week, my sister got a US visa R - B1/B2 (Type/Class). That I knew, letter "R" for Regular passport, D for Diplomatic and O for Official. But, my sister's passport is official or service passport. She is going to attend a conference in Chicago next week. So, what is really meaning of "R" ? or US embassy made a mistake and we should change the visa ?
Please help....
Please help....