Yep...that was a Bb alrighty! LOL!
I can get down to the low c but Bb is too low for me! (I was a dramatic coloratura, but over the years I seem to have become more of a contralto, but I can still vocalize up to the high c.)
The solo tenor sounds so characteristic of the Russian Tenors...so different from the sweet Bel Canto Type Tenor we associate with Italian or Irish tenors.
The Russian tenor seems to have a slightly strained or strident sound to it, I think due to Asian Influence. .
I have no idea if there is an “official” opinion on this, but it has been my experience.
There are probably a lot of “Sweet” Russian Tenors, but most of them that I have heard, especially in folk and liturgical music, sound just like the one on this recording.
It gives the music an “edge”.