Concept:A book of original entry is the accounting record in which a transaction is first written down before it is posted to the ledger.
Explanation:Sales journal and returns inwards journal are both books of original entry.
The purchases day book is the book used to record credit purchases at the point of entry.
A purchases account is not a journal or a day book.
It is a ledger account in which purchases are later summarised.
Therefore, a purchases account does not serve as a book of original entry.
Cash receipts and payments are first recorded in the cash book, which is also a book of original entry.
So, among the options, the purchases account is the item that is not a book of original entry.
Answer:B. Purchases account