Complete question:

How would a company's working capital be affected if a substantial amount of accounts payable were paid in cash?

a. it would be unaffected
b. it would fall
c. it would increase
d. the change would depend on the relationship between the payable liquidated and current liabilities

We don't answer an obvious homework question . However, think about your question. If you had $1000 in your wallet and paid $999 cash for something, what would happen to your working capital? Now, what happened to the account payable? What does it do?
What is the result?