Which of the following is not a valid declaration in C?

<ol>
    <li>short int x;</li>

    <li>signed short x;</li>

    <li>short x;</li>

    <li>unsigned short x; </li>

</ol>

(A) 3 and 4
(B) 2
(C) 1
(D) All are valid


Answer: (D)

Explanation:
All are valid. First 3 mean the same thing. 4th means unsigned.