No.
Lines 1 and 3 give the same answer in that str and str1 are the same - but not 1 and 2.
You could have solved this very easily with the debugger, or even just by writing code:
string str = "ABCDVER" + "1";
string str2 = "ABCDVER"; string str3 = "1";
string str1 = string.Format("{0}{1}", str2, str3);
if (str == str1) Console.WriteLine("Yes");
else Console.WriteLine("No");