Hi,
I was doing some text completion drill sets and came across these two words in item # 7, page 53 in guide #8 2nd ed: maven and virtuoso. I looked up these two words in Merriam Webster and they seem to be synonymous. Both indicate being knowledge and skillful about a specific field. The answer provided was 'virtuoso', while, for me, 'maven' can also fit the fill-in. Thank you for clarification.
Hanna