Factor payments are _____ and transfer payments are ________.

Which of the following options suits the best in the above blanks?

Bilateral, Unilateral

In bilateral payments, there is a two way flow. Services are provided by factors of production and in return the money is received. That is why bilateral exchanges are also called as factor payments. Unilateral payments involve one way flow only. For example, gifts and donations given. Unilateral payments are also called transfer payments.