C. employees’ social values have changed over the past ten years.
Feedback change in employee social values over the past ten years is implied in the whole paragraph, but particularly in the first sentence. Choice a is incorrect because the loyalty of the managers to their corporations is never discussed. There is no support for choice b. In choice d, perhaps career advancement is less important than it once was, but the paragraph does not indicate that advancement is unimportant to managers. Choice e is an opinion that is not supported.