Trial Balance and Suspense accounts understanding 2

Question 1)

Clanger‘s trial balance did not balance and a suspense account was opened to restore equality.
lt was discovered that:

1). telephone expenses of $673 had been entered in the telephone account as $763;
2). a purchase invoice of $2,340 had been entered in the purchases day book as $3,240; and
3.) discounts received of $264 had been debited to the discounts allowed account.

What was the original balance on the suspense account?

The correct answer is: $618 credit.
Item 1 means that total debits were overstated by $90.
Item 2 leads to compensating errors in the purchases and payables accounts.
Item 3 means that total debits were overstated by 2 * $264 = $528.

Question 2)

Which of the following errors could result in a suspense account being required to ‘balance‘ the trial balance?

A Payments to suppliers of $647 recorded as $674 in the payables ledger.
B Supplier’s invoice for $32 recorded as $23 in the purchases account.
C One page omitted from the purchase day book.
D Cash received from credit customers treated as a cash sale.

Answer is B

My question

Why have they not included error “2” in question 1) when in question 2) “B” is the correct answer??
Also why if the figures are different are the errors compensating?