$\frac{{{4}^{5}}+{{4}^{5}}+{{4}^{5}}+{{4}^{5}}}{{{3}^{5}}+{{3}^{5}}+{{3}^{5}}}.\frac{{{6}^{5}}+{{6}^{5}}+{{6}^{5}}+{{6}^{5}}+{{6}^{5}}+{{6}^{5}}}{{{2}^{5}}+{{2}^{5}}}={{8}^{x}}$

$\frac{{{4.4}^{5}}}{{{3.3}^{5}}}.\frac{{{6.6}^{5}}}{{{2.2}^{5}}}={{8}^{x}}$

$\frac{{{4}^{6}}}{{{3}^{6}}}.\frac{{{6}^{6}}}{{{2}^{6}}}={{8}^{x}}$

${{\left( \frac{4}{3} \right)}^{6}}.{{\left( \frac{6}{2} \right)}^{6}}={{8}^{x}}$

${{\left( \frac{4}{3} \right)}^{6}}{{.3}^{6}}={{8}^{x}}$

${{\left( \frac{4}{3}.3 \right)}^{6}}={{8}^{x}}$

4⁶ = 2¹² =8⁴ = 8^x

Do đó: x = 4

Vậy đáp án đúng là: B.