Algorithm A solves problems by dividing them into five subproblems of half the size,

recursively solving each subproblem, and then combining the solutions in linear time.

$$ Algorithm B solves problems of size n by recursively solving two subproblems of size n$1$ and then combining the solutions in constant time.

$$ Algorithm C solves problems of size n by dividing them into nine subproblems of size n$/3,$ recursively solving each subproblem, and then combining the solutions in O$($n$2)$ time.

What are the running times of each of these algorithms $($in big$-$O notation$),$ and which would you choose?