An include fi le can contain (A) anything that makes sense to the compiler, (B) only preprocessor directives, (C) B plus function prototypes only, (D) C plus variables of primary data types only.  The...

An include fi le can contain (A) anything that makes sense to the compiler, (B) only preprocessor

directives, (C) B plus function prototypes only, (D) C plus variables of primary data types only.

 The directive #ifdef (x , where x is an int variable, doesn’t work because (A) parentheses

have been used, (B) #ifdef doesn’t work with a variable, (C) a relational expression has been

used, (D) B and C, (E) none of them.