There are a lot of options for string literals, but which to choose as the default? I’m inclined to choose verbatim strings because I’m primarily a VB and T-SQL programmer, but the other forms do have merits.
The easiest is the one used by CSV, VB, and SQL, where in there is no escape sequences except for quotes. C# uses this as a secondary form, accessed using @" instead of the usual ".
Escaped strings are what languages like Java and C# use by default. They use the backslash to start a escape sequence. This makes strings that actually use backslashes like file paths annoying.
String interpolation, where in variables and expressions can be inlined right into the string literal. Under the covers this would be implemented using the String.Format function call. This could be combined with either of the two above formats.
Why not all of the above?
C# already offers two of the three by tacking an extra symbol to the front of a string to indicate it should be handled differently. But which to choose as the default?