For each of the following separate situations, determine how much revenue is recognized in December $($using accrual basis accounting$).$

a$.$ On December $7,$ Oklahoma City Thun der sold a $$90$ ticket to a basketball gane to be March.

b$.$ Tesla sold and delivered a $$58,000$ car cember $25.$ The customer will not pay until February.

c$.$ Deloitte signs a contract on December $1$ to provide $40$ days of advisory services with receipt of $$10,000$ due at the end of the contract. On December $31,75\%$ of the services have been completed.