Could use some help with these questions and how you got to the solution. A bit confused.

4) Smith bought a new automobile on January 1, 2020 for $30.000 and it is expected to last for 5 years. Smith calculates the annual wear and tear on his automobile to be $6,000. Therefore, his adjusting entry on December 31, 2020 should be: A) Dr. Depreciation Expense-Auto 6,000. Cr. Auto 6,000 B) Dr. Depreciation Expense-Auto 6,000, Cr. Cash 6,000 C) Dr. Depreciation Expense-Auto 6,000. Cr. Accumulated Depreciation-Auto 6,000 D) Dr. Auto Expense 6,000. Cr. Accumulated Depreciation-Auto 6,000 E) Dr. Auto Expense 6,000. Cr. Cash 6,000 5) The unadjusted balance in the Unearned Service Revenue account was $S4.000. An analysis indicated 75% remained unearned. On December 31, 2020 Smith's adjusting entry should be: A) Dr. Unearned Service Revenue 3,000. Cr. Service Revenue 3,000 B) Dr. Unearned Service Revenue 1,000. Cr. Service Revenue 1,000 C) Dr. Unearned Service Revenue 1,000. Cr. Accounts Receivable 1,000 D) Dr. Service Revenue 1,000. Cr. Unearned Service Revenue 1,000 E) Dr. Service Revenue 3,000. Cr. Unearned Service Revenue 3.000 6) Smith did some work for a client on December 31, 2020 and sent out a bill for $500. Smith should make which of the following entries: A) Dr. Cash 500, Cr. Service Revenue 500 B) Dr. Unearned Service Revenue 500. Cr. Service Revenue 500 C) Dr. Cash 500, Cr. Accounts Receivable 500 D) Dr. Accounts Receivable 500, Cr. Unearned Service Revenue 500 E) Dr. Accounts Receivable 500. Cr. Service Revenue 500