$4.$ Typically in construction contracts there will be a provision awarding damages to the buyer at $"$X$"$ amount of dollars per day for each day the builder is late in completing the work. The parties to the contract agree upon this amount in advance because they know the buyer will incur added costs, or will lose profits, because of the delay. What type of damages are these contractually fixed payments?

a$.$ Nominal

b$.$ Liquidated

c$.$ Punitive

d$.$ Compensatory