please help me with these questions

Which of the following is a major source of short-term financing that is interest free, usually requires no collateral, and is involved in some form in 7090% of all transactions between businesses? a) line of credit b) trade credit c) unsecured loan d) secured loan Banks and other financial institutions offer short-term loans not secured by collateral at interest rates that vary based on which of the following? a) the state of the economy b) the type of business c) the business's credit rating d) the owner's personal wealth