Assault Challenge 3 text inconclusive

Hi, 

with the third challenge of Assault, i had to do 1.000 damage with Grenades. 
As with other Challenges it does not specific say, that i have to do it as Assault Class. 

Would be better, to make this clear, that, if the challenge needs a specific class, it says so. 
Some of them already do, which brings this confusion. 

Best regards
Zax