Answer:
I believe it is sincere.
Explanation: process of elimination
It doesn't sound bleak or bitter and I'm pretty sure it's not matter-of-fact. I could be wrong.
The adverb " very " modifies the adjective " useful ".
“This could use more explanation/length.”
Unemployment rate can be measured in two ways, narrow
unemployment rate and expanded unemployment rate.
<span>The "narrow unemployment rate" used
for the people who are unemployed and actively seeking work, while the people
who are unemployed and available to work but have not taken active steps to
look for work are referred to the "expanded unemployment rate".</span>
