Assume a closed economy and consider gross domestic product (GDP) and net domestic product (N DP). At the beginning of 2010, firms have a capital stock of $500 million. Assume that rms purchase $200 million worth of new plant and equipment at the end of 2010. Assume a depreciation rate of 10%. As a result, GDP increases by _____________ and NDP increases by ______________ . a. $200 million; $150 million b. $200 million; $180 million c. $500 million; $150 million d. $300 million; $200 million