Which header file must be included to use the string class in C++?<iostream><string><cstring><stdlib.h>

Which header file is essential for using strcmp() function?Optionsstring.hstrings.htext.hstrcmp.h

How do you include a header file in a C program?OptionsUsing the #define directiveUsing the #pragma directiveUsing the #include directive

What is the following is invalid header file in C?*

Which of the following extension is used for user-defined header file in c++? Options hg cpp h hf

Which of the following declaration is not supported by C language?String str;Both “String str;” and “float str = 3e2;”float str = 3e2;char *str;Clear my choice