6.
A:
Ashwath Kaushik defeated a Russian grandmaster in a tournament held in Singapore.
B:
He achieved the victory at the age of 7 years and 6 months, breaking the previous record.
C:
Ashwath Kaushik currently holds a FIDE ranking of 20, making him one of the top-ranked players globally.
D:
His triumph took place at the Burgdorfer Stadthaus-Open in Switzerland, where he defeated Polish grandmaster Jacek Stopa.
The answer is: D