What makes the managerial task of executing strategy so challenging and demanding is$$

A$.$the trial$-$and$-$error experimentation that is required to come up with a workable organizational structure that can adapt to the matures stages of the industry life cycle.

B$.$the demanding people$-$management skills required, the resistance to change that has to be overcome, and the perseverance necessary to get a variety of initiatives launched and kept moving along.

C$.$the time and effort it takes to build core competencies and a robust code of ethics.

D$.$the time, training, and creative effort it takes to empower employees and teach them to communicate with their customers.

E$.$the supervisory requirements associated with getting company personnel to do benchmarking.