Answer : 4. "Apple"
Explanation :

Answer: D) Apple Explanation: Apple briefly touched $800 billion market valuation, making it the world's first ever company to hit the milestone. At $800 billion, Apple's valuation was higher than the combined market cap of all the 30 Sensex companies, which stood at $784 billion. The world's most valuable company, Apple is followed by Google parent Alphabet, and Microsoft in market valuation.