on october 3, 2018, Regal Company purchased 4200 of supplies on account.

My answer is posted below and it is partially correct, I would like to know which part is missed.

Journalizing and Posting On October 3, 2018, Regal Company purchased $4,200 of supplies on account. In Regal's chart of accounts, the supplies account is No. 15, and the accounts payable account is No. 21. a. Journalize the October 3, 2018, transaction on page 91 of Regal Company's two-column journal. Page: 91 DATE ACCOUNT TITLE DOC. POST. DEBIT NO. REF. CREDIT 1 Oct. 3, 2018 Supplies 4,200 Accounts Payable 4,2002 15 1 2 21 Feedback Check My Work a. First, identify what account is used and then what type of account is used. Every account is either an asset; liability, stockholders' equity, dividends, revenue, or expense account. Then'determine whether the account increases or decreases Each increase or decrease is recorded as a debitor credit following the rules of debit and credit (Refer to Exhibit 3 in the text). Remember total debits should equal total credits in your entry. Leaming Objective 2 and Learning Objective 3. EMS Windows b. & d. In the four-column account for Supplies, enter a debit balance of $2,020 as of October 1, 2018. Place a check mark (V) in the Posting Reference column. Post the October 3, 2018, transaction to the account. For those boxes in which no entry is required, leave the box blank. GENERAL LEDGER Account Supplies DATE ITEM POST. REF. Account No. 15 BALANCE DEBIT CREDIT DEBIT CREDIT Oct. 1, 2018 Balance 2,020 Oct. 3, 2018 4,200 6,220 Feedback Check My Work b. See the illustration in Exhibit 4 below. Every account is in the ledger, which usually uses a formal 4-column account presentation rather than T accounts Journal Entry Account Common Transaction Terminology Debit Credit Received cash for services provided Cash Fees Earned c. & d. In the four-column account for Accounts Payable, enter a credit balance of $29,900 as of October 1, 2018 Place a check mark () in the Posting Reference column. Post the October 3, 2016, transaction to the account. For those boxes in which no entry is required, leave the box blank. GENERAL LEDGER Account Accounts Payable Account No. 21 ITEM POST DATE BALANCE DEBIT CREDIT REF. DEBIT CREDIT Oct. 1, 2018 Balance 29,900 Oct. 3, 2018 4,200 34,100 Foodback Check My Work b. See the illustration in Exhibit 4 below. Every account is in the ledger, which usually uses a formal 4-column account presentation rather than T accounts. Journal Entry Account Common Transaction Terminology Debit Credit Received cash for services provided Cash Fees Earned Services provided on account Accounts Receivable Fees Earned