According to Carmichael's theorem, what is a characteristic of an element Un with n ≠ 1, 2, 6 in a nondegenerate Lucas sequence of the first kind?

A. It has at least one prime divisor that does not divide any earlier elements
B. It has at least one prime divisor that divides all earlier elements
C. It has only one prime divisor, which is 2
D. It has no prime divisors that do not divide any earlier elements
Answer: 