The correct answer is A. All flags were flying.
Explanation
A complete phrase is composed of a subject, a verb, and a compliment that also expresses a completely coherent idea. According to this definition, the correct answer is A. because it has a subject "All flags", a verb "were" and a complement "flying". Also, it expresses a complete and coherent idea.
Online contact can hurt emotionally personal contact can hurt physically
It refers to the system by which people were physically labeled in concentration camps during the Holocaust.