Which of the following situations most likely represents the highest risk of a material misstatement arising from misappropriations of assets?

Option a. Is correct answer. Others are irrelevant.

Without a doubt, it has to be Bearer Bonds.
These bonds are freely negotiable and usually of high denomination, and once transacted, tracking the bond and its money trail is very hard i.e.
fixing the responsibility of loss/ misappropriation would be next to impossible.
In other words, if it "disappears," it would be very hard to track it down, if at all.
It is, for a good reason, a big instrument in laundering.
  Again, it depends on who is the issuer of the bonds.
If it is a corporate it is relatively easier to track and pursue [due to limited issuance], but if it is a govt sec or large issuance then it would be much harder to pursue it.

a

Option a