The trial balance of Mazita, a trader, as at $31$ January $2020$ failed to agree. The difference was entered in a suspense account. The trial balance was then used to prepare draft final accounts that show a net profit for the year of RM$53,670.$

Mazita's books comprise the usual books of prime entry, including a two$-$column cash book with cash discount columns, and a single general ledger that contains all the debtors' and creditors' personal accounts.

A subsequent audit revealed the following errors and omissions:

$($i$)$ At the end of the accounting year, RM$1,500$ rent expenses were omitted from the books.

$($ii$)$ Cash discount allowed to Mazlan, a debtor, of RM$20$ has not been entered in the cash book.

$($iii$)$ Bank charges shown in the cash book as RM$430$ have been entered in the bank charges account as RM$340$ in error.

$($iv$)$ No entries had been made in the books at the end of the accounting year in respect of a stock of stationery that costs RM$100.$

$($v$)$ A sales invoice for RM$3,000$ sent to Serena has been entered in the sales daybook as RM$300.$

$($vi$)$ The debit side of the electricity account has been over$-$cast by RM$9.$

$($vii$)$ Interest received of RM$250$ has been recorded in the books as interest paid.

$($viii$)$ The total of the sales returns daybook has been under$-$cast by RM$900.$

$($ix$)$ A personal computer costing RM$2,000$ has been debited to the office expenses account erroneously. This was purchased on $1$ May $2019.$ Office equipment is depreciated at $20\%$ p$.$a on a pro$-$rated basis using the reducing balance method.

$($x$)$ The balance on the rent and rates account shown in the ledger as RM$10,000$ has been entered in the trial balance as RM$1,000.$

Required:

a$.$ Prepare the journal entries necessary to correct the above error. For each journal entry, give a short narrative containing the name of the type of error that has occurred.

b$.$ Post the adjusting journal entries to the suspense account.

c$.$ Prepare a statement showing the revised net profit for the year as at $31$ January $2020.$

d$.$ Briefly explain the reason for preparing a suspense account.