**Answer: E**

Polynomial-time programs (those whose Big O is *O(n ^{k})*
for some constant

If a program's time curves upward on a log-log plot, it is probably
*intractable*, *exponential*, *NP-complete*,
*O(2 ^{n})*, and very bad news: unless your problem is very small,
you will not be able to solve it with any amount of computers.

However, some important *NP-complete* problems have polynomial-time
approximate solutions that are pretty good.