Which of the following sentences is bias-free?()

Which of the following sentences is bias-free？()

A.The woman professor is afflicted by heart disease.

B.The old Spanish attorney was an expert trial lawyer.

C.Some restaurants have a special menu for old people.

D.Employees requesting sick leave must file the required paper-work at least two weeks prior to their requested leave.

请帮忙给出正确答案和分析，谢谢！