This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
Which of the following is an example of learned tolerance? 
Select and explain. 
A. avoiding alcohol when feeling unsteady, B. drinking alcohol only with food, C. walking a straight line when intoxicated, D. not driving when drunk
C: walking a straight line when intoxicated
Answer: C: walking a straight line when intoxicated 
Explanation: Learned tolerance refers to the reduction of the effect of a drug due to compensatory mechanisms that are learned. An example is walking a straight line despite the motor impairment caused by alcohol. This likely represents both acquisition of motor skills and the learned awareness of one's deficit; thus the person walks more carefully.