Renew Turf Inc. enters into a contract with Sports Park to provide surface material for Sports Park's baseball fields by a certain date. The contract specifies an amount to be paid if Renew breaches the deal. This clause is enforceable if the amount is

a$.$ a reasonable estimate of the loss on the breach.

b$.$ designed to penalize Renew.

c$.$ meant to pay for additional work in the event of damage.

d$.$ intended to quickly provide cash to Sports Park.