I want a grammar rule to the point.
I would like to know a grammar rule on this point because I don't understand why the reader used it in this way.
'We would be very pleased if you agreed to be a featured speaker at the program, the topic of which is “Advice on personal finance”.
I actually know something like : some of which, lots of which, many of whom. But the topic of which I can't get.
I wish I had better English, but I work hard to improve it. I'm studying for IGCSE, so I'm only interested in BrE.