If \(a < b < c < d\) and the average (arithmetic mean) of \(a\), \(b\), \(c\), and \(d\) is 10, which of the following MUST be true? I. \(a + d - b + c\) II. \(a < 10 and d > 10\) III. \(b < 10 and c > 10\)
(A)I only (B)II only (C)I and II only (D)I and III only (E)I, II, and III
B