Johnson Bookkeeping has a computer that was purchased July 1, 2019, for $1,800. Ms. Johnson thinks that the computer will be obsolete by June 30, 2021, and will have no value at that time. What is the required adjusting journal entry on December 31, 2019? A. Dr. Accumulated Amortization, Computer 450 Cr. Amortization Expense, Computer 450 B. Dr. Amortization Expense, Computer 900 Cr. Accumulated Amortization, Computer 900 C. Dr. Accumulated Amortization, Computer Cr. Amortization Expense, Computer 900 900 D. Dr. Amortization Expense, Computer 450 Cr. Accumulated Amortization, Computer 450