$AA\times BC=77\times13=11\times91$  $A=7, B=1, C=3$ 
In the calculation shown below, different letters represent different digits.  $AA\times BC\times ABC=ABCABC$  What is the product of $A\times B\times C$? 
Options:
* $$9$$ 
* $$7$$ 
* $$21$$ 
* $$13$$ 