The Assets of the Aerospace Inc On December 31st, 2013, the Fair Values of the Assets

The assets of the Aerospace Inc. (a separately incorporated entity fully owned subsidiary of ABC Transport Inc.) showed the following asset carrying values on December 31st, 2013 (in millions) : $\begin{array}{|l|l|}\hline \text { Cash } & \$ 100 \\\hline \text { Accounts Receivable } & \$ 20 \\\hline \text { Inventories } & \$ 10 \\\hline \text { Property. Plant \& Equipment (net) } & \$ 200 \\\hline \text { Patents (net) } & \$ 20 \\\hline \text { Goodwill } & \$ 75 \\\hline & \\\hline \text { Total } & \$ 425 \\\hline\end{array}$
On December 31st, 2013, the fair values of the assets listed above were as follows:
$\begin{array}{|l|l|}\hline \text { Cash } & \$ 100 \\\hline \text { Accounts Receivable } & \$ 15 \\\hline \text { Inventories } & \$ 25 \\\hline \text { Property. Plant \& Equipment (net) } & \$ 120 \\\hline \text { Patents (net) } & \$ 60 \\\hline & \\\hline \text { Total } & \$ 320 \\\hline\end{array}$
Both ABC and Aerospace Inc. adhere to IFRS.

-A gain or loss is recognized on the retirement of an asset under the following amortization system or method:

A) Inventory system.
B) Declining-balance method.
C) Composite life system.
D) Retirement system.