Juan hires a real estate agent to sell his house. The real estate agent tries to sell Juan's house but is unable to$.$ Disappointed, Juan decides to stop trying to sell his house until the real estate market picks back up$.$ A week later, Juan receives a bill for "house marketing fees" from the real estate agent. Juan refuses to pay the bill because the agent did not include fees in the original contract. What condition for exchange did the agent not meet?

a$.$

Clear communication and delivery of terms

b$.$

At least two parties involved

c$.$

Face$-$to$-$face interaction

d$.$

Freedom to accept or reject the offer