Answer:
D. 6
Step-by-step explanation:
As the two base angles are equal, this implies that this is an isosceles triangle. This means that the sides opposite the base angles are also equal.
Therefore, AB = BC
⇒ 3x = 4x - 2
⇒ x = 2
If x = 2, then AB = 3 · 2 = 6
