What is the length of DE

Answer:
Option B. The length of DE is [tex]6\ units[/tex]
Step-by-step explanation:
we know that
The triangle XYZ and DEF are similar triangles
therefore
The ratio of their corresponding sides is equal
[tex]\frac{12}{8}=\frac{9}{x} \\ \\x=8*9/12\\ \\x=6\ units[/tex]