We are given the equation of the hyperbola:
\[
3x^2 - 4y^2 = 32
\]
To put it into standard form, divide through by 32:
\[
\frac3x^232 - \frac4y^232 = 1
\]
Simplify each term:
\[
\fracx^2\frac323 - \fracy^28 = 1
\]
The standard form of a hyperbola with a horizontal transverse axis is:
\[
\fracx^2a^2 - \fracy^2b^2 = 1
\]
Comparing, we see \(a^2 = \frac323\).
Thus:
\[
a = \sqrt\frac323 = \frac\sqrt32\sqrt3 = \frac4\sqrt2\sqrt3
\]
The length of the transverse axis is \(2a\):
\[
2a = 2 \times \frac4\sqrt2\sqrt3 = \frac8\sqrt2\sqrt3
\]
Therefore, the correct answer is \(\frac8\sqrt2\sqrt3\).