Step 1: Understanding the Concept
Points A, B, C, D are coplanar if \([\overline{AB}\ \overline{AC}\ \overline{AD}] = 0\).
Step 2: Find the vectors
\(\overline{AB} = (1, 0, p-2)\), \(\overline{AC} = (0, -1, 1)\), \(\overline{AD} = (1, 1, -2)\).
Step 3: Determinant
\(\begin{vmatrix} 1 & 0 & p-2 \\ 0 & -1 & 1 \\ 1 & 1 & -2 \end{vmatrix} = 1(2 - 1) + (p-2)(0 + 1) = p - 1\)
Step 4: Solve
\(p - 1 = 0\), so \(p = 1\).
Final Answer:
The value of p is 1.
\[ \boxed{\text{(C) }1} \]