Final answer:
The purchase of sugar and flour by Main Street Bakery has a neutral immediate impact on GDP. It's when these ingredients are used to produce and sell finished goods, like cakes, that an increase in GDP would be reflected.
Step-by-step explanation:
The spending scenario described, where Main Street Bakery buys sugar and flour for cakes, would generally be accounted for in the GDP by the BEA (Bureau of Economic Analysis) as intermediate consumption if these goods are used in the production of final goods (cakes) that the bakery will sell.
Since GDP measures the total value of finished goods and services produced within a country during a specific period, the increase in GDP would occur when those cakes are sold, not when the bakery purchases ingredients. The immediate impact on GDP is neutral; however, the effect on GDP will be seen when these goods lead to the production of final goods that contribute to the economic output.