When a stick is divided into 4 equal parts, the length of each part is $\log_5(x)$ units, and when divided into 10 equal parts, the length of each part is $\log_5\left(\frac{x^2}{25}\right)$ units.
Accordingly, what is the length of the stick in units?\\
A) 5\\
B) 8\\
C) 10\\
D) 12\\
E) 15