The key words in the stem are: "a single line segment of finite length"

Now, answer choices A, B, and C can not be correct answers as solutions sets for these exponential functions are not limited at all (>= for even powers and <= for odd power) and thus can not be finite (x can go to + or -infinity for A and C and x can got to -infinity for B). As for D: we have that absolute value of x is between two positive values, thus the solution set for x (because of absolute value) will be two line segments which will be mirror images of each other.

Answer: E.

Just to demonstrate:

A. x^4 >= 1 --> $x\leq{-1}$ or $x\geq{1}$: two infinite ranges;

B. x^3 <= 27 --> $x\leq{3}$: one infinite range;

C. x^2 >= 16 --> $x\leq{-4}$ or $x\geq{4}$: two infinite ranges;

D. 2 <= |x| <= 5 --> $-5\leq{x}\leq{-2}$ or $2\leq{x}\leq{5}$: two finite ranges;

E. 2 <= 3x+4 <= 6 --> $-2\leq{3x}\leq{2}$ --> $-\frac{2}{3}\leq{x}\leq{\frac{2}{3}}$: one finite range.

Answer: E.