RTY is a calendar year corporation. On December 12, RTY billed a client $17,800 for services rendered

Question:

RTY is a calendar year corporation. On December 12, RTY billed a client $17,800 for services rendered during October and November. It had not received payment by December 31. On December 10, RTY received a $4,000 check from a tenant that leases office space from the corporation. The payment was for next year’s January and February rent.
a. If RTY is a cash basis taxpayer, how much income should it recognize from the above transactions this year?
b. If RTY is an accrual basis taxpayer, how much income should it recognize from the above transactions this year?