This should be simple but I can't seem to get it.

Which of the following is not considered cash for financial reporting purposes?
A petty cash funds and change funds
B money orders, certified checks, and personal checks
C coin, currency, and available funds
D postdated checks and IOUs

Think Logically

(a) and (c) are actual cash or cash equivalents therefore included in financial statement

(b) is not actual cash but can be realized in cash i.e. cash equivalents required to be included in financial statements

Now we have no other choice EXCEPT (d), is not cash or cash equivalents.

Postdated cheques are nothing but a signed paper like bills written with IOU's.