Final answer:
Brian's company is valued at $10,000,000 if he is offering a 5% equity stake for $500,000. This valuation is found by dividing the investment amount by the equity percentage.
Step-by-step explanation:
Brian is valuing his educational software company. If he is offering a 5% equity stake in exchange for an investment of $500,000, we calculate the total valuation of the company by dividing the investment amount by the percentage of equity offered. Therefore, the company is valued at $10,000,000 because $500,000 is 5% of $10,000,000. This means the correct choice from the provided options is d. $10,000,000.