Consider line \(\ell\) containing points P(1, 1, 1, 1) and Q(1, 0, 4, 3). Let \(\vec{u} = (u_1, u_2, u_3, u_4)\) be a direction vector for line \(\ell\). Which of the following statements always must be true?
1. \(u_1 = 0\)
2. \(u_2 = -1\)
3. \(u_4 = -2u_2\)
A. none of them
B. 1. and 3. only
C. 1. only
D. 2. and 3. only
E. all of them