Suspense account (kaplan kit 23-24)

Q1. Savvy Co had a suspense account balance of $1,300 in its general ledger. This balance related
to the accounting for an increase in the allowance for receivables. The increase in the
allowance had been correctly recorded in the allowance for receivables account but the other
accounting entry was posted to the suspense account pending the junior accountant making
further enquiries.
What accounting entries are required to clear the suspense account?
A Dr Irrecoverable debts expense $1,300 Cr Suspense $1,300
B Dr Receivables $1,300 Cr Suspense $9,000
C Dr Suspense $1,300 Cr Receivables $1,300
D Dr Suspense $1,300 Cr Irrecoverable debts expense $1,300

The answer given is C.. i dont understand why is it C? wouldnt it be A?

and there was also this other question regarding correction of errors

Q2. Tangerine Co made a sale to a credit customer for $500 plus sales tax at 40% which was
recorded correctly in the general ledger. The customer subsequently returned half of the
goods as they were damaged upon receipt and a credit note was issued for that amount. The
entry for the credit note in the receivables account was made correctly and the other entry
was made for the same amount in the returns inwards account.
What journal adjustment should Tangerine Co make to correct this error?
A Dr Returns inwards $50, and Cr Sales tax $50
B Dr Sales tax $50, and Cr Returns inwards $50
C Dr Sales tax $100, and Cr Returns inwards $100
D Dr Returns inwards $100, and Cr Sales tax $100

The answer given is B.. i dont get this as well.. at all.. how is the tax 50? wouldnt it be 100 if half are being returned?

thank you.