Well, we know how the algorithm
C running time grows - it's linear, and it's two-side (lower and upper) bound.
However there is still not enough information to choose the best (meaning: fastest in practice) algorithm here, because:
- We know only upper bounds for algorithms
B - they might be more efficient than
C actually, we just don't know that yet.
- We don't know constants, hidden in the $\Theta$ bounds - they might make the algorithm
C less practical than
B for limited problem size.
Using the given information we can say only that for some sufficiently large problem size the algorithm
C might win over algorithms