To see which value is different, count the total number of $$0$$\textquotesingle s in each product. 
Of the following, which has a value different from the others? 
Options:
a. $$40\times 50$$ 
b. $$4\times 5000$$ 
c. $$50\times 400$$ 
d. $$40\times 500$$ 