17. A line passing through the origin, together with the lines $x=1$ and $y=1+\frac{\sqrt{3}}{3} x$, forms an equilateral triangle. The perimeter of this equilateral triangle is ( ).
(A) $2 \sqrt{6}$
(B) $2+2 \sqrt{3}$
(C) 6
(D) $3+2 \sqrt{3}$
(E) $6+\frac{\sqrt{3}}{3}$
17. D.

As shown in Figure 4.
Notice that one side of the equilateral triangle passes through the origin, while the other two sides lie on the lines $x=1$ and $y=1+\frac{\sqrt{3}}{3} x$. Therefore, the equation of the fixed side is $y=-\frac{\sqrt{3}}{3} x$.
Thus, the intersection points of the three lines are
$$
\left(1,1+\frac{\sqrt{3}}{3}\right),\left(1,-\frac{\sqrt{3}}{3}\right),\left(-\frac{\sqrt{3}}{2}, \frac{1}{2}\right) \text {. }
$$

Therefore, the side length of the equilateral triangle is $1+\frac{2 \sqrt{3}}{3}$, and the perimeter is
$$
3+2 \sqrt{3}
$$