Question 25
The three numbers are $A=\underbrace{3\times\cdots\times3}_{40\text{ factors}}$, $B=\underbrace{5\times\cdots\times5}_{30\text{ factors}}$, and $C=\underbrace{7\times\cdots\times7}_{20\text{ factors}}$. Their order from largest to smallest is _______.