> 3. Which of the following aren not legal types in C?

a. `short unsigned int`
b. `short float`
c. `long double`
d. `unsigned long`

Answer:
b. `short float`

> 4. If `c` is a variable of type `char`, which of the following statements is illegal?

```c
char c;
// A:
i += c; // i has type int
// B:
c = 2 * c - 1;
// C:
putchar(c);
// D:
printf(c);
```

Answer:
D is incorrect because `printf` operates on strings.