Which of the Following Sentences Is an Example of a Mixed

Which of the following sentences is an example of a mixed construction?

A) Gary and Joan were both asked to attend "sensitivity" training.
B) Alex was ill with a fever, so he asked his manager if he could be excused from work.
C) Laura is busy preparing for tomorrow's big presentation.
D) Because my boss refuses to negotiate with clients resulted in us losing the deal.
E) She was asked to reduce the planned operating expenses in order for her budget to be approved.