Which of the following statements about characters and strings in $C$ and Java are true?

A$.$ Strings in $C$ and Java use null $(0)$ to mark the end of a string

B$.$ Strings are just an informal name for single$-$dimension arrays of characters in $C$ and Java

C$.$ A string in $C$ takes about half the memory as the same string in Java

D$.$ Operations on strings, like length, are faster in C than in Java