Final answer:
The four key parties in a loan signing are the lender, the borrower, the cosigner, and the creditor holding collateral. The lender supplies the loan, the borrower is responsible for repayment, the cosigner provides additional security, and collateral may be seized if the borrower defaults.
Step-by-step explanation:
The four key parties involved in a loan signing are the lender, the borrower, a cosigner (if applicable), and the creditor who holds the collateral. The lender provides the funds for the loan, while the borrower is the individual or entity that receives the funds and is responsible for repaying the loan. A cosigner is an additional party who agrees to take on the responsibility of repaying the loan if the borrower defaults. Collateral is a borrower's asset that is pledged to the creditor as security for the loan and may be seized if the loan is not repaid.