Which of the following is the best example of bias-free language? (A) Every flight attendant must submit her security clearance card before boarding. (B) All managers and their wives are invited to Friday's cocktail party. (C) The servers at Cafe Divine are always professional. (D) Two firemen will collect the toy donations.

Answer: Option C

Explanation: In simple words, bias free communication refers to the communication of message which does not discriminate any individual on the basis of their profession, race or gender etc. and does not make any assumption about them.

In the given case, all other options other than C were making assumptions about the individuals or differentiating them among others.

Hence the correct option is C.