Answer: Loan commitment or credit line
Explanation: A loan commitment refers to a promise under which the lender commit to provide a loan of a specified amount to the borrower. Similarly, a credit line refers to the amount of money that a credit card holder can use from that account.
In the given case, the construction firm wants to show that they can have necessary funding. Thus, they can use above tools to show that they have the back of banks in case of providing funding.
Thus, the correct option is C or D .