bank reconciliation

Hallo,

In this example:

The following bank reconciliation statement has been prepared by a trainee accountant:
$
Overdraft per bank statement 3,860
less: Outstanding cheques 9,160
5,300
add: Deposits credited after date 16,690
Cash at bank as calculated above 21,990
What should be the correct balance per the cash book?

Answers:
A $21,990 balance at bank as stated
B $3,670 balance at bank
C $11,390 balance at bank
D $3,670 overdrawn.

Correct answer:
– 3,860 – 9,160 + 16,690 = 3,670. Remember that the opening bank balance is overdrawn.

My Q: What is the difference between answer B and D is, meaning, if we have an o/d balance in the bank, wouldn’t it be also overdrawn in our cash book, as I thought the correct answer is D? It looks like if we have an o/d balance in the bank, doesn’t mean it is o/d in the cash book?

Thank you!