Answer:
B and H.
Step-by-step explanation:
By the triangle inequality, any two sides of a triangle must be greater than the remaining side. 
Triangle 1)
The side lengths are 9, 40, and 41. 
We only need to check the two smaller sides. 9 + 40 = 49 which is indeed greater than 41. Therefore, this is indeed a triangle. 
Remember that if: 

We have a right triangle. 

We have an obtuse triangle. 
And if: 

We have an acute triangle. 
In all of these, c is the longest side. 
Therefore, we will substitute 41 for c and 9 and 40 for the others: 

Evaluate: 

Since the two values are equivalent, the first triangle is a right triangle. 
Triangle 2)
Again, adding up the two smaller sides gives that 8 + 10 = 18. 
However, 18 is less than 21, so it does not satisfy the triangle inequality. 
Therefore, the given side lengths cannot form a triangle.