Question

Let vector a = 3i + 2j + xk and b = i - j + k, for some real x. Then vector |a x b| = r is posible if –

A.√3/2 < r ≤ 3 √3/2
B. r ≥ 5 √3/2
C.3 √3/2 < r < 5 √3/2
D.0 < r ≤ √3/2