An ip address in the form 197.169.100.1 is called a(n

In my email i got a message it says a quick message and in message details on who its from its says nicole and under nicole is [email protected] -

2pointswho was mikhail gorbachev? oa. a russian leader who opposed a coupob. a polish leader who founded the labor union "solidarityoc. a soviet leader who called for a closer relationship with the unitedstates, economic reform, and a more open societyd. a soviet leader who called for more oppression in the soviet union

Which of the following "invisible" marks represents an inserted tab?