What was the @ sign used for?
(Отметьте один правильный вариант ответа.)
Варианты ответа
Ray Tomlinson used the sign to identify the protocol.
Ray Tomlinson used the sign to identify the mail server.
Ray Tomlinson used the sign to write a letter.
Ray Tomlinson used the sign to designate the receiving machine.(Верный ответ)
