 Plant Assets Cost: For plant assets, which are tangible fixed assets such as buildings and machinery, the cost includes all expenditures necessary to acquire the asset and prepare it for its intended use. This includes the purchase price and additional costs such as design and construction.

This aligns with standard accounting practices where costs related to bringing an asset to its operational state are capitalized as part of the asset's cost.

 Intangible Assets Cost: The cost of intangible assets, such as patents and trademarks, typically includes the purchase price and development costs. However, option B refers to this, but the correct focus for plant assets is emphasized in option A.

 Amortization of Intangible Assets: Intangible assets with finite useful lives are subject to amortization, contradicting option C. Those with indefinite lives are not amortized but tested annually for impairment.

 Expense of Developing Plant Assets: Development costs for plant assets are capitalized, not expensed immediately, making option D incorrect.