need adjusted entry

Scenario D-Unearned Services Revenue. The company charges $100 per month to spray a house for insects. A customer paid $600 on November 1 in advance for six treatments, which was recorded with a debit to Cash and a credit to Unearned Services Revenue. At year-end, the company has applied two treatments for the customer 1)Determine what the current account balance equals (before adjustment). a) The current account balance before adjusted $600 2)The current account balance should equal $400 as of December 31 (two months at $100 per month). b) Current account balance Dec 31 is $400 3) The current account balance should equal $400 as of December 31 (two months at $100 per month)