answer: Mrs. Wang wants payments by D/A or D/P because a letter of credit would increase her cost, but #Person2# insists on payment by L/C because it gives the additional protection of the banker's guarantee.
documents: #Person1#: Well, we've settled the question of price, quality and quantity. Now what about the terms of payment?
  #Person2#: We only accept payment by irrevocable letter of credit payable against shipping documents.
  #Person1#: I see. Could you make an exception and accept D / A or D / P?
  #Person2#: I'm afraid not. We insist on a letter of credit.
  #Person1#: To tell you the truth, a letter of credit would increase the cost of my import. When I open a letter of credit with a bank, I have to pay a deposit. That'll tie up my money and increase my cost.
  #Person2#: Consult your bank and see if they will reduce the required deposit to a minimum.
  #Person1#: Still, there will be bank charges in connection with the credit. It would help me greatly if you would accept D / A or D / P. You can draw on me just as if there were a letter of credit. It makes no great difference to you, but it does to me.
  #Person2#: Well, Mrs. Wang, you must be aware that an irrevocable letter of cred it gives the exporter the additional protection of the bank er's guarantee. We always require L / C for our exports. And the other way round, we pay by L / C for our imports.
  #Person1#: To meet you half way, what do you say if 50 % by L / C and the balance by D / P?
  #Person2#: I'm very sorry, Mrs. Wang. But I'm afraid I can't promise you even that. As I've said, we require payment by L / C.