For reading and updating an existing fi le, fopen uses the mode (A), w, (B) w+, (C) r+, (D) a+. To read a character from a disk fi le, the function to use is (A) getc, (B) fgets, (C) getchar, (D) none...

For reading and updating an existing fi le, fopen uses the mode (A), w, (B) w+, (C) r+, (D) a+.

To read a character from a disk fi le, the function to use is (A) getc, (B) fgets, (C) getchar,

(D) none of these.

For sending diagnostic messages to the standard error, the function to use is (A) fputs,

(B) printf, (C) fprintf, (D) all of these, (E) A and C.