Which of the Following Is an Example of a Trade-Off

Which of the following is an example of a trade-off imposed on an organism that results in a medical problem?

A) Patients who became infected by a novel flu strain had had no previous exposure to that particular strain.
B) Sturdier bones would prevent fractures but would also slow down organisms mobility.
C) The crossing of air and food pathways in humans increases the risk of choking.
D) Recent changes in human diet contribute to metabolic diseases.