Final answer:
Bill Gates currently owns approximately 0.53% of Microsoft, as he has reduced his stake over time through sales and donations.
Step-by-step explanation:
As of today, Bill Gates no longer maintains a significant ownership stake in Microsoft. The correct answer to what percentage Bill Gates owns of Microsoft is A) 0.53%. Over the years, Gates has sold or given away much of his stake in the company, diversifying his holdings and contributing to his charitable foundation, the Bill & Melinda Gates Foundation.