1.The standard header _______ is used for variable list arguments (…) in C. a) <stdio.h > b) <stdlib.h> c) <math.h> d) <stdarg.h> AnswerAnswer: d [Reason:] None. 2. va_end does whatever. a) Cleanup is necessary b) Must be called before the program returns c) Cleanup is necessary & Must be called before the program returns d)…