2003 AMC 12B Problem 6

The second and fourth terms of a geometric sequence are 2 and 6. Which of the following is a possible first term?

\text {(A) } -\sqrt{3} \qquad \text {(B) } \frac{-2\sqrt{3}}{3} \qquad \text {(C) } \frac{-\sqrt{3}}{3} \qquad \text {(D) } \sqrt{3} \qquad \text {(E) } 3

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.