Final answer:
The Blue Spruce Corp. should report its plants at the historical cost of $350 million on the balance sheet. Current fair value is not used in this instance for financial reporting.
Step-by-step explanation:
The Blue Spruce Corp. has five plants nationwide that cost $350 million. The current fair value of the plants is $580 million. According to accounting principles, when a company reports its assets on the balance sheet, it should do so at their historical cost, not at the fair value. Therefore, the correct answer would be: c) $350 million. The value of the plants is based on the initial cost at the time of purchase and stays as such on the balance sheet unless depreciation or impairment must be accounted for.