Wells Fargo Bank lost face in the corporate world, its CEO and its Head of Retail Sales resigned, and the bank paid penalties to regulators and restitution to its customers. Which of the following can be seen as the primary reason for this downfall?

a. Engagement of employees in upselling rather than in cross-selling, despite management's focus on the latter

b. Presence of employees who acted as whistle-blowers when unethical activities occurred within the bank

c. An incentive plan that focused more on intrinsic rewards than on extrinsic rewards

d. A negative organizational culture that overemphasized meeting sales targets