Let w, x be two arbitrary column vectors (k by 1) with the same number of elements (k). Which of the following statements is not true: 1. w'x = x'w 2. wx'=(xw')" 3. w x = xw 4.2* (w + x) * 2 - 4w + 4x a. 1 b. 2 c. 3 d. 4